KYC is all about tax, that´s the reason behind, they (Binance) holding assets on your behalf, and they had to fullfil the rules from your countries financial laws and that of the EU also, and the bigger your assets are the bigger there hunger for taxing it will be, that´show the system works. You gain something and they ask for their "fair share" of your profits for which you before had shoulderd the risk alone, that´s risk minimizing par exelence.
The marriage certificate has to do probably also with the tax situation depends on your countries tax rules, capital gains are normaly directly tied to the individual not to the couple, maybe there is some deeper concerns behind it, better be prepared.
The matter has now been resolved with Binance, but it took time.
I had to get a bunch of documents to be approved by them
glad to hear that ;)
Regardless of the rules, the marriage certificate was strange
That's why I'm asking if others have been asked that question
I agree with @don-t, they require a marriage certificate for tax reasons.