“Polish” in this sense doesn’t refer to bug count, but to user experience. There are many details in PGO that make it a better experience than Ingress, many of them so small you don’t notice until you compare head-to-head, like the ability to rotate the map with one finger in PGO, while you need two in Ingress. The way most people hold a smartphone while walking, you only have one finger useable.
I do agree with the assessment of walking-for-walking. I have the same experience, Ingress is very strongly goal-based even in where you go, while the Pokestops are more like POI — you go there, roughly, maybe. It’s not so important, and especially not very important which one you visit. In Ingress very often you need to get to that one specific portal to build up your field or tear down one.