Spaces and end of sentences in まんが

Question

Up until now, I think have I never seen a space in the Japanese textbook I'm using (Genki). However, when I started trying to read this まんが, I realised that, sometimes, there are spaces. Since this one is the very first I'm reading, I don't know if it's specific to this series, or happens normally. Anyway, I've attached a picture where this appears (last panel, on the left, between また and すげー).

Due to the lack of punctuation, I'm guessing this is a way of separating sentences, but I'm not sure. Another option that comes to mind is that it is used to facilitate the reading, like how they do it in children's books. Still, that shouldn't be applicable here (at the very least, this isn't supposed to be a book meant for children, I'd say). Could someone clarify this for me?

Answer 1

Translated from NAVERまとめ:

With most manga publishers other than Shogakukan (which uses more standard punctuation markers), it is an implicit rule to use spaces instead of the reading and punctuation markers, and users of the internet who are influenced by reading these manga and its lack of punctuation are numerous.

In other words, depending on the publisher, they may use fewer or more punctuation markers and you just have to get used to that style.

Edit: As @Ringil mentions, this applies mainly to periods and commas. Exclamation points and question marks are used fairly ubiquitously, as they are needed to convey any tone that would be unrecognizable without them.
It should also be mentioned that often ellipses take the place of spaces, depending on the publication.