I felt the convenience of never worrying about a key outweighed the threat of theft.
You'll only forget the key once, then you'll have 2-3 spares wired up in hidden places on board like I do.

The key in our boats is just a vanity thing, it is quite possibly the easiest thing in the world to "hot wire" with 2 pieces of wire, paperclips, anything really.
True true. My 8yr old could probably hot wire it!

I actually worry more about dropping my car keys (+home +work +everything) in the drink than losing the boat keys.