Once upon a time, washing machines had open top-loading tubs.
And vertical axis spin dryers.
Typically these were on casters, brought 'out' for use, and allowed to oscillate gently on their casters while spinning. Cables (and hoses) notwithstanding.
Agree absolutely with JBM, fastening the thing down means that the forces get used to flex the extractor and its mountings. The less of that going on, the less chance there is of fatigue failure of welds in the stainless.
I'm delighted with my smooth-running Park motorised extractor. But last year I had some of my late-harvest frames with a touch of crystallisation, which meant that the balance was constantly changing, and had the thing vibrating disconcertingly.
Hence, a mounting board with ball casters is already on my list of things to do before my next extraction session.
I think this should be a better solution than buying the optional roller casters to attach to the extractor's legs.