When the start menu gets long and even more when it overflows it is nice to have folders for eg. games, office apps, image apps etc.

The main reason I like the start menu is that I sometimes forget the name of applications I use seldomly and I forget what apps I have installed.

Edit: One thing I forgot to whine about is the configuration panel. In the old one you had everything in front of you instanly. The new one is a joke and I never seem to remember which feutures you need can change in the "mobile friendly" blue one, or the kinda a folder one.