I think that's good advice, but I don't think the reg requires it.
It's sort of like flying on instruments in the clouds at night, which I used to do regularly. You can just blunder along and follow the needles, but I always kept a picture in my head of where I was, both vertically and horizontally. It's sort of an organic version on the "Synthetic Vision" that's commonly available for GPS on Part 61 aircraft, although obviously nowhere near that precise.
Full disclosure: I've never flown a drone with
goggles, although I will eventually. And my intention is to use a Visual Observer when I do, at least initially.
Thx,
TCS