Obviously starting a takeoff roll with flaps extended will mean you are pulling against a certain amount of drag for the whole takeoff run.
There is an argument that leaving the aircraft clean until near rotation speed will mean that the takeoff run will be shorter.
There are a couple of negatives
1
Obviously you are now on your own as Manufacturers will not publish takeoff data for clean runs with flap extended near rotation.
2
This adds an extra distraction and extra room for making an error.
3
This requires precise handling
4
Question whether that reduction in drag is worth the other risks ie if it only saves a few feet!
Going back to the original question re snow? There are numerous variables which make snow takeoffs imprecise.
How deep is the snow? Is it fresh snow or frozen into sheet ice below the powder covering? Is it dry powder snow or slushy porridge like snow.
(any skier knows how snow can change from solid ice to porridge over the course of a few hours.
To a certain extent you are in the realms of test pilot so an absolute no no on minimal runways or landing strips!
Have an abort point with plenty of stopping distance left if the aircraft is not accelerating as it should be.
Landing go steady and be smooth on braking action any doubts on the surface go around
Pace