Because what if the power cycles in the middle of a write sequence? ...I suggest that you look into battery backed up RAM, which at least doesn't have the endurance issue.
BBRAM also must be coded to handle "power cycles"
BBRAM also has 'endurance' however not measured in 'writes', but in years
it is a misnomer to speak of endurance re writes, it is erases that wear it out. If it was writes "walking writes" would have no benefit.

Erik