I guess the answer is you don't have to have them on stands no, they will work whereever and if that's all you've heard they will sound fine. It's just they can and will sound better with proper positioning and stands, it just depends how much that is worth to you with the effort/cost ratio.
I used to have mine on the unit, but moved them to stands and I personally think they sound better. I bought the Atacama Moseco 10 stands from Peter Tyson. Cables route down the back tube (although I had to elongate the holes for bi-wire). Then filled the front tube up with those Atabite things.
I've got the Atacama Moseco XL600 filled with atabites too, they weigh a ton!
At my old place on a concrete floor the spikes were fine, but in my new room I've got a floating wooden floor and coupling the stands to that with spikes was casuing real issues! So looking around at isolation solutions and came across an amazing product from the USA here, called Herbies Gliders
https://herbiesaudiolab.com/products/threaded-stud-glider?variant=12651505745975
Since the equivalent products would be Isoaccoustics or Townshend, these are giving an equivalent performance for a fraction of the price tag.