From your link, it looks like that limitation is for the amazon appstore (I didn't even know they have one).
From the looks of it, the specific referenced restriction is regarding apps available on a "store" that android users access to download apps for their android phones. This store appears to be similar to the google play store, and the iTunes app store for iPhone users.
I don't believe the specific restriction is regarding hosting anything related to crypto on AWS infrastructure.
The best VPS to launch a casino, exchange, mixer is one you own. Let me be more specific: It's one nobody else can access, but you. The reason is simple: You can't trust middlemen with this sensitive information. Take a mixer for example. If you host a mixer in a VPS, it means you're trusting that the real administrator won't report you to the authorities with the first request, and secondly but more crucially, he won't spy on you.
Same as with running a full node at home: A person who's hosting a mixer, a casino, or an exchange needs to prioritize security and privacy.
If you are running anything on a personal basis (for example sending/receiving transactions on your personal account), a self/at-home run full node will maximize security/privacy.
Hosting the backend infrastructure for an app is generally going to be a business doing so. Having an employee (or a founder) hosting the backend in their basement is almost always going to be a bad business practice. Further, any app that is going to run at scale is going to
have to be run out of a data center, either via the data center that is housing the VPS you are using, or the data center that is hosting a server you own (or the server you are renting). If you are using a data center, there is always the risk that the operator of the data center is going to spy on you -- there are precautions you can take to prevent and/or detect when you are being spied on, but there is always the risk. Even if you aren't running your backend out of a data center, whatever you are doing can be traced back to your ISP, and your ISP can give up your information to the government.
If you want to protect yourself against spying by your data center, your best bet is to use a data center that you can trust will not spy on their customers at scale. From there, you can try to remove the link between what the public sees and your back end infrastructure -- this most likely means running your services through tor.