yes, you can tell mame to use the y axis instead of the x axis.
But after that... I have both... And I didn't really play any spinner games on my cab until I got a spinner... and I had a trackball for about a year at that point.
If you like spinner games, get a spinner. If you like trackball games get a trackball. If you like both, consider if you can fit both or hotswappable.
Sure the trackball can be used, but its not the same.
Also note. Getting a spinner thats geared is much better for arkanoid and such.... So I could see getting 2 spinners and a trackball.,..