I only use my Garmin for GPS+heartbeat based workouts such as hikes + my runs. I've never had any issues integrating their services into Strava or a variety of workout devices in gyms. Though, on a sidenote, it is beyond annoying when many of those devices only support Ant+ or Apple HealthKit integration; but I wouldn't really tag that a Garmin issue as much as an ecosystem one.

That all being said, I could imagine more complicated workouts that surpass simple lap/leg tracking could be problematic.