I know at least one professional classical guitarist who regularly goes to a nail bar to have his nails done with silk wrap, and I have known other guitarists who use gel. All seem happy with the process.

Personally I've never needed it, even playing steel strung. My nails are moderately strong, with just enough give in them to stop them breaking too easily when they hit something. (My classical guitar case does have stick-on nails in it for emergencies, but I've never needed to use them).

Mick