The reason off-mirror PDAF sensors maintain some AF advantages even today is because they can be purpose built to more accurately measure phase differences and predict the correct distance the lens has to move. On sensor PDAF and DPAF elements are constrained in their design and therefore in the information they can provide. That's why after 10 years comparatively few MILCs have AF which is as fast or as confident as SLRs on initial acquisition, or as capable on point tracking (as opposed to AI subject tracking).In THEORY, using the sensor is far superior. Period.
So no, using the sensor is not far superior in every way period. That doesn't mean MILC AF won't eventually match or exceed SLR AF in all respects. A lot of effort continues to be put into making MILC AF as good as or better than pro sports SLR AF. But they have to rely on more sophisticated software, processing more data points more times per second, to try and beat a simple, purpose built PDAF module.