Tesla has a long history of including features in hardware and locking them with software to help simplify its production while keeping costs in check. However, this is one of the most obvious examples of it — your AWD Model Y can already accelerate this quickly, it just hasn’t been given the option until now.
This is also a defensive move. Tesla has tried to block unofficial performance hacks for a while. An Acceleration Boost might reduce the temptation to use those hacks while giving the automaker a way to profit well after you buy an EV.