Definitely a little weird and raises some flags, it also makes me feel like it's a beta and not out of development, not something you want to risk a lot of funds with.
Raising flags is not necessary in my opinion, it has nothing to do with scaming people I think. But I am sure your second point is valid, they are still in a very early development phase. In such a phase it makes sense to regulate and control the amount of users who have access to the site. So they are able to tune their system (more servers, more database, ...) before they go public. On point.
Btw, every person on this thread is very welcome to ask for invite link to tower bet, it will be sent via PM here.
