I assume they were afraid they’d get beaten for the check (that it would bounce); they need your info so when it isn’t honored they’ll simply take it from your balance. I dealt with Wells Fargo years ago, and am glad to be rid of them.
I gave them my account number and they could see I had money to cover the check. Besides, it was a check from their bank.
I think it is a new government policy and they were simply obeying.
A friend wrote a check, made out to me, on his local Bank of America checking account.
I walked into that Bank of America to cash it. They wanted to charge me $7.50 to cash it.
I shut up and walked out. Took it to my Credit Union - no problem.