Back in the day, before cryptocurrency was worth anything, an email address and a password was all you needed to login to an exchange. Then came 2FA, using email verification or Google Authenticator. Then came the third generation of secure sign-in methods, and that's when things started getting weird.
From Fit the Puzzle to Make the Gesture
As attackers have gotten more sophisticated, so have the measures cryptocurrency exchanges have taken to keep them at bay. These are designed to fulfill a range of objectives, including spam and bot deterrence, as well as to perform increased due diligence for legal reasons.
Binance with its "Fit the puzzle piece carefully" which has spawned numerous memes, and kept its customer support busy attending to users who can't fit the puzzle. Kucoin, meanwhile, began asking odd questions of its customers a few weeks ago, and then repeating those questions every time they went to login, much to their annoyance.
Kucoin asks the important questions