I avoid using step models in my libraries and only uses the simple altium extrusions.
Once the library gets slightly big the step files take up WAY too much space. library and PCB files become huge. I don't like it.
We use Altium at work, and we have step file models in all of our library components. Including more "complicated" components (mechanically complicated anyway) like switches, connectors, etc. Our libraries are literally many hundreds of MBs in size. They are quite slow to load.