Drilling set up on the lathe

[nova_robotics]

If your vice has vertical jaws and will securely and squarely hold the part then there are dozens of reasons why you may want it in the future they just haven't made themselves known to you yet.
I have used tool holders on my tool post as a vice many times this also affords me a limited amount of vertical adjustment as well or clamped a larger part to the tool post itself with a good "C clamp
they are great for finishing out an 80% lower if you don't have a mill or other suitable ridged machine to spin the spinny tool as you called it

It's got up and down. The cross slide on my lathe does the side to side. The compound could do angles or something I don't know. It's actually kinda nice, it has a self centering vise. I thought that was a neat little feature.

I have a halfway decent mill though. I bought this because I have an addiction.