Is there an android app for this?

You have a couple options. Install it to your homescreen as a PWA or install @Alby Go and connect to CoinOS using Nostr Wallet Connect. The connection QR can be found in the CoinOS wallet settings.

Why?

The features they have included, mostly, and complete lack of any KYC needed. They have: Nostr Wallet Connect eCash for privacy Lightning address for receiving zaps BOLT12 Easy to use UI And I am sure I am missing something. As always with custodial solutions, you are absolutely at risk of being rugged, so don't keep much on there. Personally, I am using Alby Hub on my own Start9 with a parallel CLN node for BOLT12, so I have all of the above features, except the eCash part, completely self-custody. For those who just want an easy custodial option, though, it's hard to argue with what @Mysterious Hamster has going for them.