EVERYONE does.
Your seller side CC SOMETIMES auto populates to the buyer side.
EVERY seller has a buyer account, as in Amazon terms, the Buyer Account is the “master login.”
This is why when drop shippers abusing prime get suspended on the buyer side they can’t log into the seller side.
It’s also why when sellers “close” their buyer account they can’t log into the seller side.
Same.
Ok, but if I never use that seller central account login for buying anything, only for seller central, and have a different (corporate) name, address, email, phone, and credit card number for the seller account, from the personal buyer/customer account one uses to purchase stuff on Amazon, so it has no connection to the seller central account, correct?
The idea of complete isolation is perhaps a bit paranoid, but we also use computers dedicated for Amazon seller stuff that are used for no other purpose, not even for internal emails. They are nothing but “terminals” hooked up via web browser to Amazon’s “mainframe”. No connection to any other use. Is that sufficiently “air gapped”?
It is still associated.
The “Buyer Side” is the master login. Every Amazon account MUST* have a buyer account, otherwise you can’t login to seller central. That’s just the way Amazon works unfortunately.
(*I’m sure there are exceptions, but for sellers that’s how it works. This is why when people close/delete/get suspended as a buyer, they can’t log into seller central)
As another example of this relationship – when I had to call Amazon as a buyer they were going to make me enter the verification code for log-in (I was already logged in of course.)
I explained that my codes are sent to my landline, which is the phone I am using to speak to you. This won’t work.
So I had to go into the buyer side and disable two-step verification. Then call back.
So when that was over I could not get into the seller side without re-establishing my phone for sending log-in verification.
Let me be very careful here to clarify things - I understand that the seller account CAN purchase if it is so foolish as to do that, but if we have:
[email protected] for the seller account and [email protected] for the buyer account.
Two different phone numbers, two different mailing addresses, two different credit cards, each with different names (the corporate entity vs the individual customer) and appropriate different addresses as billing addresses, and a separate bank account in the name of the entity, not the buyer’s name.
Further still a unique IP address for the office, with those computers only used for the seller account, no personal business is ever transacted from that location at all, so the entire router and subnet at that site is “unique to amazon seller business”.
How the HECK are they gonna tie the (home) buy-only account to the (work) amazon seller account? There’s no connection at all, other than one of the employees (me) just happens to also buy occasional camera gear from Amazon from home, using completely different resources.
No those are not associated.
But [email protected] has a buyer account, even though you never use it or signed up for it.
That’s me then. I have just one buying account.
I wouldn’t be too concerned about it. You’re not running some corporation with that account that you would want to sell off at some point.
You’ve been around long enough. Amazon isn’t going to bother you with nonsense.
A lot of people talk about all these bad things that will happen with this and that. The reality is those situations are pretty rare and I personally think they have actually gotten better with their false positives the last few years.
You’re Good 
Oh OK - I am fine with that, as [email protected] will never buy as much as a toothpick from Amazon, as he was not born in the turnip patch a week ago yesterday. 
We have three (active ones; I think there is at least one dead one linked to an old email).
To me it makes sense. Nisha and I each have a personal account, and we have an account for business use. Even if the account was not directly linked, we would want a separate account for the business, as that makes bookkeeping far easier (and as I’ve been told by an IRS employee, goes over much better if audited; hopefully I never get to verify that). So why not use the linked one for business purchases? Seems odd to not do so.
Yeah, I don’t completely understand the “fear” of buying with the “seller” account.
Products and supplies that I need for JoeBcrafts (keyrings, wood beads, masking vinyl, wood biscuits, paper bags, magnets, packing tape, hardware, etc) if purchased on Amazon are through the JoeBcrafts “seller” account.
I don’t leave reviews.
Stuff for home we buy through the wife’s account that carries Prime.
The OP’s situation could happen to any account.
Same for us. We use the linked (primary) Buyer-side account for business-related purchases.
I tried to register an Amazon Business account to that account a few years ago, but it glitched so badly and repeatedly that I abandoned the effort. I just mainly wanted to see how our B2B offerings appeared, anyway, not purchase through that channel, so nothing lost.
I finally opened a “Business Account,” but the discounts are minimal unless buying large quantities for most items. That type of account requires the use of an ordinary credit card, not the Amazon Prime card that offers 5% off on purchases from Amazon itself.
I have purchased one item so far, and saved about 10 bucks.
I use Amazon American Express, which offers 5% off Amazon business purchases.
Annual fee? Discount at Whole Foods and Amazon Fresh?
Most of what I sell are one-offs, so offering a discount to businesses, who can also take advantage of 30-90 day delayed billing would not benefit my business.
No fee. Not sure about Amazon Fresh.