Would this 10 sec limit mean that the Variable Geometry turbos start to overheat quickly in the overboost mode, or is it just a marketing tip to impress customers??

I guess that both torque AND power increase with this function, by briefly increasing the turbo pressure.That would give between 5 and 10 extra bhp, am i wrong?

What do tech specialists think about it?Are VTG less reliable than others, would it be more difficult to tune these kind of engines??