if you like the formal version & there is any possibility that you would like to give your child the option I would use it. However, there are exceptions like you really hate the full name (as is the case w/ us and
Maggie, we hate
Margaret or
Ben &
Benjamin), or if its a shorter version that is acceptable (like
Lily or
Maggie, more & more), but for something like
Charles whats the big deal? As for
Katherine I would never name my child
Katie, but would consider
Kate w/
Katie as a nn. Furthermore, the argument that certain names don't suit certain professions is just nonsense and you'll find every name in every socio-economic category (Candys can be anchors & Elizabeths can be strippers).