Well, this is a free game. They have to get income from
somewhere. It's nothing unusual, every free-to-play will eventually have to resort to incorporating payments as much as possible into the core gameplay, even if they were only optional to start with. Otherwise, only a very small percentage of players will actually pay, and it costs money to keep the game up. It's standard from for all of this type of game; you can't expect to have the best game experience if you don't pay any more. It's annoying, but the aim is for the ads to 'nudge' players towards buying tokens by interrupting gameplay every so often until they pay. Expect more of this kind of stuff, because they have a decent-size playerbase and these methods are lucrative. It's based of a known psychological trick that game developers can use, where they prevent players from having a continuous, uninterrupted experience unless they pay. It has worked extremely well in Facebook games before (although with much larger interruptions that last multiple hours, unless you pay), and often people get impatient and pay.
tl;dr Tacticsoft are playing off a tactic that most free-to-plays use nowadays.
I don't play much anymore. I've found other games to play and I've seen pretty much everything that SM has to offer in the 2 years I've played. Still, it's been fun.
