Oh, well darn. I wouldn't put the idea completely out of the question though, especially in this day and age. Decompressing to a temporary folder would almost defeat the purpose of storing them compressed, unless the temp folder was cleared every time the emulator was closed. This could severely fragment hard drives over time, but for flash storage i don't really see the issue.
Considering the N64 was in the same generation as the PS1, its kind of amazing that the N64 roms are so small.. they packed a lot into those cartridges
BTW, i just found the No-Intro roms