It is helpful for catchers to know their pop times and their velocity. Both are important! Some need more improvement in catch and throw technique, others need more improvement on arm strength. The best catchers are good at both.
Pop times will always be better in workouts than games. In games the catcher is receiving live in game pitches with a hitter that is likely to swing. In workouts, the catcher is receiving BP slow fastballs mostly thrown right down the middle and no worry about the hitter swinging.
Typically catchers pop times in the 1.8s during workouts would be 2.0 or more during games. We try to get all in game pop times, but sometimes it just doesn't present itself. And good in game pop times can be the result of the type of pitch and location of that pitch.
Maybe the most neglected thing to evaluate is foot work. But in the end if you lack the necessary velocity you will never reach the highest level. Most all high level catchers have very strong arms. Sometimes they are former pitchers and shortstops.