Premade exploits are always going to be a risk, so you need a way to prevent that from happening. All of the different exploits rely on one thing, and that’s to manipulate the pool size of the players you can get matched up with to a size small enough to have a high chance of ending up together. So with another option to queue, that’d be a real possibility, especially in the segregated Russian pool.
If rewards are “worth it”, it drives away people from the other pool, which affects both the possibility for premades to form (why do it if you don’t earn more from doing so), and also motivates even more desperate attempts to perform premade exploits.
And you argue this is for fun. So why do you ask for rewards?