I do get those, but not that I think they're good. You have to understand the design philosophy is not to make a good game. It's to make a game that's addicting and wallet draining.

The timer does two things. It makes you plan your time around it, always coming back as timers end (often with notifications when they finish). It also creates an obstacle they can sell you the solution to. Its pretty antithetical to good game design, but it's profitable game design.