A 比 B （更）聪明 = A is smarter than B A 比 B 还聪明 = A is smarter than B, given that B is already smart A 比 B 还要聪明 = A is even smarter than B, given that B is already smart ( with some emphasis) But in real life they are very similar. With or without 要，the meaning of the sentence will not change. I would say 要 emphasizes the fact that A is smarter.

The main meaning of this useless 要 here -- is to give you the felling "omg, Chinese is so confusing and difficult" while in fact it's as easy as English.