And, when you follow, the @#name# is what is saved in your cache.
So, your display name can change minute-by-minute and your followers don’t have to re-up each time.
I compare it to a physical address. Your screen name is like the name on your address. The @ part is the physical address. So, this morning I changed my Display Name to TN Conservative (from Shegens). My @Shegens address didn’t change. If you search a person’s @address you will find them and not the other 50 people with a similar display name. It’s really a good flexible setup. Too many try to search the display name and then don’t know which one to pick.