Respectfully, I disagree. I use this routing function all the time to use paths in my area. Sometimes you have to adjust it, but it is leaps and bounds better than routing from Google (and probably Apple even though I haven't used it). It is true that if a particular area doesn't have a lot of cycling activity, the data isn't going to be as good.Nope.
This is a heat map of *people who use Strava* which is pretty much only sports & recreational cycling. When I ask Strava for a route to/from work... it wants me to ride as though I'm in a peloton of 50 with no traffic on the roads, rather than the most direct & safe route. That isn't even on their silly heat map, nor are most dedicated bikeways (because the roadies don't use them...).
It's an extremely biased routing algorithm. Great if you want a sporty ride for exercise in an unfamiliar environment.
There is not cut and dry "best route" for any area, but in my experience for long distance and in the city, Strava routes has given substantially better routes than google, especially in areas that I am not familiar with. If you are cycling in your own city or area often, chances are you already know the best routes to use and don't need a routing function.