It's just another one of the panelling basics. Space between your panels has all kinds of uses.
It can be used to make a scene feel more slow-paced, or to create a sense of unease (like if you're building something up).
Also, it can make the panels feel more claustrophobic if they're far apart? I have been using panel distance quite a lot myself to play with pacing for horror for example. The more vivid and intense scenes are closer together and even overlapping. The more calm but uneasy parts have some distance and gaps.
Another use is to emphasise the meaning of dialogue - if you want your dialogue to stand out you can leave a space blank and put your word balloons in there or something. You can leave a lot of space around a small illustration to make a metaphor for isolation or anxiety or something like that. You can make your page cluttered (but still coherent) with panels to make it seem erratic or chaotic.
Panelling is pretty complicated! Sometimes people apply these techniques seemingly at random due to lack of understanding, but most creators are able to come up with a lot of great storytelling with it.