Thats the bottom line, Just like Mike Mas said it.

You want it to hold the heading solid, Ya gotta buy Heading lock.
BUT;
Piezo is fine for learning and sport flying.
Hell, I did it with an old mechanical gyro.
It's actually going to make you fly the rudder more, So isn't a bad thing to learn. One recommendation, practice while facing the wind until you can hover nose out ok.

Ramjet