There must be individuals who have made huge profits still from trading cryptocurrencies on exchanges. To these people, exchanges are the best and they will in a second recommend it's use to other new traders who seek their opinions. I am not saying I am right, but I think that whatever works for you is good enough, and if you are profiting from trading on exchanges, it is okay to still focus on it as long as you are able to maintain your profit margin and possibly improve it.