CBS app was rebranded as Paramount+ app and I tried the 1-month free trial. I don't remember the CBS app but the current app has a litany of shortcomings:

• No picture in picture support. I love watching a video while playing a game so this is an important missing feature.
• On older shows the subtitles are really bad. I guess they use the original close captioning and often it's based on the script no the actual episode. But even for newer shows cc often lags behind the audio.
• Really bad show descriptions. Like a one sentence description of the show (not episode, the whole show) and nothing about the cast.
• Can't favorite shows or any way to mark shows for watching later. It does keep track of what episode you are on and where in the episode.
• For some shows (e.g. JAG) it doesn't have every episode. For JAG after season one it seems like half the episodes are missing. I'm guessing maybe due to copyrighted music.

For just watching shows it's ok so I guess this app compared favorably to a dumb television. But compared to the competition the Paramount+ app definitely hurts the service.