I think this is a good analysis of where the offline idea started from, but in my experience the majority of interviewers who want you to do a "take home" thing are asking you to sign up for a multiple-hour mess of a project. That's where the lack of respect comes from, and the lack of acknowledgment of the market--most people you want to hire are already employed, after all, and time pressure from life is a thing.

Making it an option for somebody who would rather wouldn't be bad, but yeah, as you say, nobody's learning a lot about the other people that way, and they're probably more important.

(The OP's card deck problem is just faintly ridiculous and a bad allocation of the candidate's time, and I assume there are more hoops to jump through afterwards.)