And as a buyer in this case I don't like this option.
If you selling stuff you gotta be serious about what you doing and its not hard to update info and delete 1 domain from 2-3 websites if you sold it. Professional sellers will do it.
If Flippa rejects not approved users that's fine, no one like scammers, but allowing sellers cherrypick is not good for business either. When you press that button deals is made and must be executed. Otherwise why even bother with buying through BIN if you know it's not for certain and seller can back out of agreement to sell? People must think twice BEFORE setting BIN price, not AFTER. I will rather buy on GoDaddy than, because I know for sure, that if I hit BIN button domain will end in my cart and after I pay it's mine. Boom!
Clear process of buy/sell is what separates serious business like GoDaddy from 2nd-tier companies like Flippa. That's pretty important aspect, imho, you can see that GoDaddy cares more about buyers and Flippa about sellers. Maybe because they make most money of sellers?!
My conclusion from this experience: buy on GoDaddy, sell on Flippa