Scrimp is resin infusion, that means the
mold was put under vacuum and the resin was "sucked" in by vacuum (or pushed in by atmospheric pressure). The major benifit of this system for balsa is that each and every void is filled with resin.
Water intrusion is not nearly the issue it is with "hand laid" glass.
In my opinion, having had balsa core on my own
boat, balsa is my least favourite core. BUT, if it's infused (Like SCRIMP) then it's as good as any other core, with it's own merits and downfalls.
Water simply does not migrate through an infused core.
Click here to see why hand laminated balsa sucks:
http://svocelot.com/Ocelot/ThaiRefit/Week26.htm
Cheers.
Paul.