A copuple of days ago I have found several changesets, from two different users, realigning roads (which at first seems not to improve OSM data).
I asked both users about their criteria for the changes and now both users answered that their were using Strava data (Strava imagery within JOSM)
AFAIK, Strava sumarizes tracks taken during ycling and running or walking, so it seems to me that the tracks tend to be in the outer border of the road, or outside the road.
On OSM the road models the center of the road, so I doubt that, in general, aligning OSM to Strava imagery is a good idea. Maybe in some case is good, like cycleways or footways.
Mostly I use the Strava heatmaps in JOSM to check that the aerial/satellite imagery is reasonably well aligned. There seems to be far more tracks and better averaging of their locations than the OSM uploaded tracks so I think you are better off checking alignment with Strava than with OSM tracks. If the aerial/satellite imagery shows a cycle lane then you can assure the heat map is lined up on that, you don’t need to line the heat map on the center of the motor vehicle lanes.
Often the heat map will show two parallel lines, one on either side of the road. Not a problem, now you know where the edges of the road should be lined up with the aerial/satellite imagery.
In areas where tree cover hides sections of the road (or more usually hiking/bicycling trails) from aerial and satellite imagery the heat map layer is a very useful thing for locating the center line of the way.
So yes, I use Strava heatmaps in JOSM to help when editing. And I note that in the change set comments.
I have been making a few tracks along a new rail line and have been expecting the assistance of a few Strava tracks too, but so far no Strava data is showing.
Does anyone know how often the Strava data is updated on their heatmap or available to use in JOSM? It appears to me to be from about 2015 and none later.
I have found the Strava data very useful for track and satellite alignment and yes you do need to bear in mind it may be at the side of the road or on a cycleway, along with most gpx tracks.