This Oculus Go is very similar to a phone headset, since they aimed for a modest price point. It's a little better than the Samsung headsets, but only a modest improvement.
Unless you've tried it, I think it's really unfair to say Go is a modest improvement. The optics for one are much better than even the rift - not to mention you don't get dust inside the headset to ruin the experience.
Go also has a Snapdragon 821 for ONLY VR. The GearVR was sharing resources with a ton of other garbage background processes that Go doesn't need to worry about. And the thermal performance is also way better.
Finally, you can get Oculus Go to run at 72Hz which is a way more comfortable experience than GearVR.
So you get a lot more than your phone can give you for 25% of the cost.
Sadly the Snapdragon is woefully underspecced in it's video decode capability - tops out at 4K which is less than ideal - 5K HEVC are already popular and a noticeable improvement for VR video.
I don't think it's all that popular yet, most 360 content I see is 4K and anything better than that is fairly rare. I do agree it's needed but especially for mobile VR storage requirements are also an issue that keeps people from releasing at better quality.
I bought one this morning (heck, I actually bought two- got lucky at Best Buy) I agree it's better than the GearVR, but it still seems only modestly better to me- I agree the optics are definitely better.
As you say, it's a good deal given the modest price point.