smurfs

i just wander why does LOL allows smurfs in ranked ?? if they want to try learning a new champ they can do that in normal ?? there is no reason for smurfs to exist some people says that you can learn from them but that is a joke most the time you will just get rekt and honestly a bronze player can never learn anything from a high tier player he lacks so much things to start learning from high ELO . and isn't smurfing the main reason why you can buy an E-bay account ,because no smufrs=no one can boost the accounts etc .... i don't see any reason why you should allow smurf to exist if so please enlighten me some one.