...I buy music...
I don't really care of people buy music but champions should be earned through sweat and blood imo.
Buying champions just means you have one less thing to throw IP at. And to be quite honest with there only being 2 game modes that are actually relatively short in queue time it can get tedious earning the IP and then you still have runes for optimization.
Yeah it an be inefficient. But it's also a good incentive for practice.