I don't know about the guts of that one specifically, but most of the "mouse" trackballs don't have bearings in them.
They are made to be precision pointing instruments, and do a really good job at that.
What they DON'T do is continue to roll, like a real arcade trackball.
I've had good luck using the mouse type for games where you want precision pointing, like Centipede.
They have issues for other games, where you want to "roll" the ball, and have it follow through.
It's alot like spinners.
The spinner for Arkanoid is designed to precisely position your paddle to hit the ball.
The one for Tempest is designed so that you can spin it hard, and it will keep going.