I would say they are practically worthless, I have a bunch. The pcbs cant be converted to mvs games, the ICs are also basically useless. About the only thing worth anything is the shell, I have found some that are basically NOS.
Pretty much, unless you are restoring one of these print stations. Or want to harvest parts. If you get the cart(s) try to dump them to see if they are in mame, for preservation sake.