I would now if someone can help me and say if I need a industrial grade or not to insure reliability in a PC embedded device. I use linux and make the most filesystem in RAM to avoid read/write of the cache or the var folder.
I use CompactFlash cards running the RouterOS software as part of my daily operations. I have never had a CF card fail yet in 3 years of operations.
It's hard to tell exactly what you're asking, but I'd say the answer is yes. Lots of people use CF cards as the main OS disk for special purpose linux servers.
Flash memory is viable as storage. Look up "Solid State Drives" or "SSD"