More than a "killer app", it has a "killer feature": even though it isn't full AR, it is "Passthrough VR"... with cameras of high enough resolution, that you can use a physical keyboard (VR keyboards stink big time), or your smartphone, without taking it off.

There is nothing more jarring with VR headsets, than having to take it off every time you want to interact with something IRL, even things as simple as taking a sip of water.

disposable item

There will come higher quality, lighter, more efficient versions in the future, but that doesn't make this one "disposable", it's likely to get some support (especially with right to repair legislation) and work well enough for at least the next decade.

PS: INB4 anyone calls me an "Apple fanboy", I wouldn't even consider getting one until it gets jailbroken, rooted, and allows dual booting into whatever alternative OS.