Why the telelever front suspension?

A bmw rep once told me that the Boxer twins have more control when braking because the front shocks don't compress that much like other motorbikes. So..when you brake hard on a R1150GS or R1200GS the bike remains level once can almost say, more control in handling and blah blah.

First off, what is the real benefit of this suspension to that of other bikes and, If there is real benefit to this telelever and paralever suspension, why has other not really copied it?  Just a question..