@SketchSpud that's a good write up. Should only be able to accept one scout invitation though. remember you can look at the profile of the person offering you membership, and see who scouted them at their art page. Making a good choice avoids being "pruned" where someone higher up the branch gets the whole branch dropped for poor judgement/rulebreaking.
SketchSpud
If you check the undiscovered artist filter in the "latest" section of the Art Portal, you might get a bit of a better idea of how it helps. The undiscovered art section is filled with tons of sketches, spam, and a general art quality that's lower than what's usually found in the art portal. Since Newgrounds does not have an algorithm based feed (like Twitter or Instagram), it would make it horrendous to get your art noticed if someone had to scroll through every art piece posted today to find it. This is why the Art Portal/ being scouted is so important since it eliminates the noise and makes it really easy to find new artists!
Being scouted shows off that your art can consistently hit a certain mark of quality that the portal can see as well as a trust that you won't be breaking any of the posting rules. Your scout essentially put a good word in for you to the mods and the users of Newgrounds. That being said, picking your scout(s) is your choice of who you think put in the best word(s) for you. If your mod is a Newgrounds Veteran whose been scouting people for years, they're probably a safe match. If you're unsure, scouts have to be scouted in order to scout; meaning that there is a generally a layer of safety when it comes to getting scouted. I also believe that you can accept multiple scouts but idk much about that because I haven't seen it happen as often?
If your scout ends up getting banned, you will lose your recommendation since their word is untrustworthy. If you have multiple scouts this would drastically decrease the likeliness in which that could happen. Even if you get out of the portal because of a bad scout, it shouldn't be too much of a problem because your art has already reached the Art Portal quality and will be easy to spot/re-scout! Sorry for the essay lol hope this helps (it's my understanding of it at least)!