Put your hand on the floor (suspended, not slab) next to spiked speakers paying dynamic music with plenty of bass content and you can feel the vibration on the floor…do the same with Vibrapods (or other things that turn vibes into heat…like my cousin Shirley) and you should ( or will) feel zero vibration from the speakers. That’s the difference.
Right. I get it. And true in your case if this is your experience. However, I'm not convinced (granted I haven't tried) that would necessarily be the case with my speakers on carpeted wood flooring, and more importantly whether or not it *should* be the case. I think what you're referring to would be a complete "decoupling" from the room, and I'm not sure speakers that are producing low bass should necessarily be completely decoupled. But I'll conceded that "pointed spikes" in the traditional sense (like still points) may be less desirable than the Vibrapods in certain applications.
My problem with spikes and footers is that every time I've ever raised my speakers using them - and that includes several different speakers - I've found a change for the worse.
And this is why the most appropriate answer to the thread title, with the assumption "necessary" implies improved sound quality, is "it depends".