I believe that’s roughly what @mstenta was describing when he mentioned progressive enhancement.
It doesn’t look like that’s a final version. Even once it’s adopted by OGC it’ll probably take a while for major GIS software applications to fully support it.
I would guess it would be wiser to implement one of the previous WFS specs unless there’s something particularly compelling in the WFS 3.* specs for these use-case(s).
I think @paul121 said he had experimented with a QGIS plugin in conjunction with farmOS.py a long time back.
My assessment more recently is that implementing a standard geospatial API like WFS is a much better value proposition because it could be used in other GIS applications, not just QGIS.