I know, it's one of those things they use to deliberately make their game worse in the hopes you will pay to make the problem go away.
Let me make you a counter-offer. I'll pay something one time to make the energy system suck less. You can even charge me dollars instead of crystals, which for all you know I have been slowly stockpiling for free.
Just kidding, I did do the weeklong subscription thing. I like paying for games that I feel earn it. Playing a game you truly enjoy and going out of your way to do it for free is a little unethical, I think.
So yeah, the problem arises when there is a game I enjoy that does not sell anything I want to buy. I don't like temporary boosts or random loot. Though your random loot box at least has no "losing" plays.