It's supposed to mimic a gelled flash, so in theory it is a good idea. I've avoided the flash Holgas for a couple of reasons. The batteries tended to fall out of the older flash Holgas (Pre-n series) and when I do want to use a flash, I strap my $300 Nikon SB-800 on top of my $30 Holga! I have bought all my Holgas from Randy Smith at
Holgamods, and he only modifies the non-flash version.
I'd like to hear from someone who uses the flash version through. Maybe I'm missing out on something.
Bob