The varifocal lens sounds potentially bulky, noisy, slow, fragile, and frustrating (e.g. if it focuses on a bush in front of you that you're trying to look through to see the baddies on the other side). Magic Leap's approach is more brute-force, but really so much more elegant.
On the other hand, I'm all for room scanning. Definitely hope we see that in Santa Cruz. Makes much more sense in an untethered HMD, although it would probably burn a lot of battery power.
The extra FoV sounds nice, but not sure that's the way I'd want to spend so much additional resolution. If they have a good foveated rendering approach (i.e. better than the static one in Oculus Go) that can deliver a "free" resolution bump to accommodate, then perhaps.