Pathfinder main here, i love how NOBODY uses him, i consistently have him all to myself!
I suspect this is because the grapple hook & zipline have a learning curve to them, combined with the fact that on the surface they don't seem that valuable. On top of that most people i matchmake with are surprised when they find out what his passive ability can do, most people don't even know how to use it.
In summary Pathfinder not only lives up to his name as the best at guiding his team through the map with intel and macro re-positioning, but also as an individual unit his grappling hook gives him unparalleled re-positioning utility and speed which is extremely useful for running to respawn beacons, getting high ground instantly during a fight to escape or 1-up the enemy, and also general reconnaissance. His ult has the fastest charge out of all the legends, use it to bring your teammates on top of towering buildings with you, or to set up a quick escape if you get surrounded.