But leave the vast majority of your show to a machine, while you play a minimalist part (if anything), and where, exactly, IS the difference between you and karaoke?

For one there is no TV screen with displayed lyrics. In fact here is no music video or CDG.

No members of the audience can select a song to sing.

The backing tracks are MINE..not recordings of the original arrangement

I guess its that people who feel they are "excellent players" have to separate themselves from the rest with semantics in order to support their elitism. In the end the money is the same and the everyday club audience doesn't care how many years one took lessons. The just want to hear Margaritaville and Sweet Caroline. Not Paganini. they don't care if one is playing or wandering the room.

Karaoke requires more than just a background track.

by definition: an act of singing along to a music video, esp. one from which the original vocals have been electronically eliminated.
-Random House dictionary

a device that plays instrumental accompaniments for a selection of songs to which the user sings along and that records the user's singing with the music; also : a form of entertainment involving the use of a karaoke machine

-Websters

By shear definition leaving the keyboard and singing cannot be described as Karaoke at all.