So I have a Namecheap account and trying looking at an .app domain just now, but it says "We don't support this TLD". Because of this I am now on GoDaddys page pre-registering there.
The GoDaddy thing is basically, "Pay us extra and we'll click for you automatically on May 8th." It's like paying Southwest Airlines $15 to check you in right at t-minus 24 hours before your flight...