What it boils down to is that, in extreme examples, it becomes a strict race to buy boosts to promote your streams. Smaller streamers who can't afford to compete in a buying race are just out of luck against those who can.
That's the problem. Paying to boost your own stream can easily become a buying race, which makes it even harder for unknown streams to get traction unless they can afford to keep up.
There's also the fact that the streamers don't actually directly make anything off of boosts. So paying into it is essentially just feeding Twitch unless you're one of the rare few who truly does make it.
Perhaps I'm being overly critical, but I'm really not fond of such a system. I don't really stream, but it still seems really shitty to those who do.
The rich must always get richer or else the commies win.