Fingernails are FINE, in fact, they're
very useful for detatching flat LEGO tiles from each others,
my older brother used to always ask me for help with them, because he had made the bad habit of chewing on his fingernails, so his were very weak for that work.
On the other hand (ha!), toenails ARE weird, and a mildy unfuriating nuisance
- they serve no pratical purpose
- they hurt like hell when you stub them
- they can get hooked on your sock's strands, which is uncomfortable as hell
- (only somewhat in the case of my pinky, especially for older people) they get swallowed by the skin and/or grow in weird clumps of keratin