Very strange choice to present the player with a solved puzzle and no "scramble" button...

The demo is a 60-second teaser, it was never the game. In the app you get a free pool of scrambles, then one rewarded ad refills it. The next update makes it about ten scrambles per ad, and nothing ever interrupts a game. It is a one-man company, the solvers and servers are paid from this.

scramble is a paid feature on their app.

Even now when you turn off the Solver Menu in settings you have 10 free scrambles within one ad refill (unless you use another premium feature in the meantime)