So member.cash is an instance of Member - it's there to make it easy to see how it all works.

Member is open source, so you can host a mirror on your own infrastructure. You might make that mirror available publicly, or you might use it privately. Shutting down all the public instances would likely be a game of whack-a-mole. Similarly, its not dependent on AWS, or a gmail address.

While a single website might be vulnerable to DDOS, the vision is many independent instances which will allow for great redundancy.