I tried to import in QGIS a layer from a PostgreSQL table with a geography type column created through the extension PostGIS.
I noticed that QGIS doesn't seem to like the geography column...
Here the step to create the column...
ALTER TABLE traffico ADD COLUMN geog geography(POINT,4326);
then to update the column...
UPDATE traffico SET geog = ST_GeogFromText('SRID=4326;POINT(' || lon || ' ' || lat || ')');
but then when I connect QGIS to my server I see this:

There's no way I can find to tell QGIS to treat my column as a geography type instead of geometry type. Indeed if I try to upload the layer like this the point coordinates do not correspond to reality.