I say, it is to give crewing maximum flexibility to shaft you wherever possible !
It certainly gives greater potential.
But what all this "rostering at minimum notice" really does is to allow minimum staffing levels, saving on cost. The penalty is chaos for all (yes, including "poor old" Crewing),
the result of which is ruination of aircrew lives/friendships/marriages/sleep patterns/health.
Since only aircrew are affected, not profits or schedules, then it'll persist until aircrew stand up for themselves.
Seems, from the general consensus here, that aircrew regard the ruination of their lives as "perfectly normal", so you've only got yourselves to blame!
Some of you even seem proud of the disruption you put up with! One born every minute (luckily, for the likes of bmi)