As a 15+ year veteran programmer, I of course have checked their Android app.  I can assure you that this app is NOT a cheap webview app.  This app looks like a very solidly built app as I did sign up and tested it out for a few days.

They received a 4.2 rating on Android Play Store with thousands of users already on their beta app.  To build something like the Sphere app would take at least a couple of programmers one year to build due to the complexity of building a social network.

So, judging on their product, this is NOT a scam.