If you are limited with time but want to get some exercise, if you're rusty with your climbing abilities, if the weather is so-so or if you want to simply stay close to town, this is the place!
All of the above applied to me at one time or another on several occasions. It is exhilarating watching really young kids just going fearlessly up the hard rock, no guidance at all, all their moves so natural. If we adults could only emulate them!
This is a good wall for training, very convenient to get to with many different routes. It's great if you have a just few hours as it's so close to Chamonix. Oh, and it does have some very nice views from the top!