highway=bus_stop is a place where passengers waiting. In Poland is very common to place it at shelter's location.

Merging with highway=platform which is only addition here may be unwanted, it can also produce false-positives for validators which checks if highway=bus_stop is no on the highway – it's a very common issue that mappers place highway=bus_stop on the street instead of near the street, which is invalid for ptv2.