I have to agree. At my gym, the people who seem to track their training mostly use paper notebooks. Even the younger people who otherwise live on their phones or post instagram videos of all their lifts. I don't notice many people using apps. Though it can be hard to tell, because e.g. a smart watch may be tracking some things automatically, or an app may have computed the workout in advance.

I personally don't track anymore. I was using a Google Sheet on my phone but it didn't really seem to add any value. Now I just remember what my reps and weights are for the main lifts I do.