The point is that you login with an email and the <your-email>.ln2.email becomes your lightning address to redirect to whatever wallet you are currently using (and also your NIP-05 address).
This way you can easily switch between wallets without having to tell all your friends to update your details and not send you money to the old address. 

 However, if your service is down, I don't get sats?
Correct? 

 It’s running on https://vercel.com
It never holds any funds - only redirects http requests.