Regular tables are softer
Regular tables are softer, especially if you table select a bit. Zoom tend to attract a lot of grinders, and even casual players play less hands on Zoom, because the format takes away some of the boredom of waiting for decent starting hands.
The advantage of Zoom is, that it is somewhat easier to focus on each hand, you play, if you are playing a single Zoom table rather than 3-4 regular tables, which you need to get the same amount of volume. And of course there is no waiting to get in and out of tables. So if you only have like 20 minutes to play, Zoom is perfect.