In the case of the pricey Yamaha, if you have a suitable room (one with enough reflective surfaces) it does a quite amazing job of providing immersive, multi-channel sound without having any speakers at the back of the room. It won’t work well if you cover all of your windows and walls (and ceiling) with curtains or other sound-absorbent treatments. Similarly, it isn’t magical - it won’t create surround-sound effects in a barn.
If you watch, or just listen to, a lot of surround-sound content, and you don’t want a traditional 5.1 or larger setup with speakers scattered about the room, this is an impressive alternative. As you note, the technology doesn’t come cheap.
Personally, I’m decidedly old skool, and am quite happy with our 5.1 system.