Jalolov just won the World Amateur Championships, he is however the exception to the rule. As for the original question, I have no issue with it, top amateurs are essentially pro's now anyway (with stipends, soft jobs, government payments, a government team including trainers and nutritionists). Some of the top UK amateurs were better off in the amateurs than they were in the pros. The reason to do both is to fight for your nation (amateurs) as well as your pocket (pro). As as an emerging pro your competition in the amateurs is likely much better than being in the pros for those early bouts.