About the only thing missing on the CA-30 is an output jack. If you have pickups on an instrument, they'll give you a better signal than the "clip-on" contact mike, and it's occasionally handy to be able just to run through the tuner and leave it hooked up.

But of course, this only applies to people who "play amped" who are usually performing and making the big bucks for it (joke?) - so they'll probably want a little more sophisticated tuner anyhow.

John