I have replaced more tubes from broken Presta valves then flats I have got in the last 20 years.
There are several advantages to Presta valves, with the main 2 being that a. they are less likely to lose air both on a ride or when stored than Schreder valves, because of their design and the fact that there is a lock for the air release
Schraders are MUCH more forgiving and less likely to be damaged. That is absolute horse crap that the Presta seals better. Once the valve closes the air holds it closed. The higher the pressure the harder it is pushed closed. The Schrader was inveted to over come how much of a pain in the butt a Presta is and the fact that when the valve does have a problem it can be replaced without throwing the tube out.
Tubes loose air from microscopic holes more so then leaking valves of either style. The higher the pressure the more it can force trough those little holes
There is so little of a volume of air in a bicycle tire that the loss of volume on a 700x25 of that that drops a 100psi tire to 50 psi wouldn't even register as a loss on the average tire gauge if you lost the same volume of air on a car tire.
