I'd argue that being able to use sql to more easily combine ans filter datasets, including non-geospatial ones is still very useful in the circumstances you described.
Not really, combining datasets in (Geo)Pandas is very straightforward, including spatial joins: https://geopandas.org/docs/user_guide/mergingdata.html#spati... Of course, it's all a matter of personal preference, but I have used both PostGIS and GeoPandas extensively.
