This seems to be a nice project todo in your spare time. Buying it? No thanks, I don't see how this will benefit me. Selling these for 500$+ ? You must be joking.
I got no mail, and was signed up for ai, ml, db.
It seems only ai is open to registration so far, perhaps to get an idea of demand and discover bugs...
Questions like this seem a bit pointless in my opinion. I mean sure, a lot of people get to answer with their insights and opinions on the said language/tool, but in the end isn't everything you learn going to benefit you and make you a better programmer? So asking if something is worth learning will probably always get a positive answer because the more you know the better (even if you don't get to use that specific tool you ask about).