It's not easy to just tune out posts from some members, especially if they are creating many topics with empty discussion.
No, you're definitely right about that. I have an extensive ignore list, and I just added
325btc to it because of all the vapid, stupid threads he's been creating. I'm 99.9% sure he's an alt of Polo7 and a few other accounts, all of which I have on ignore as well. Aside from that I don't add too many members to it anymore, because I found out through time and experience that I just can't keep up with all the new accounts posting idiotic nonsense.
Not trying to put every shitposter on ignore makes it easier to report their posts, if you're into that kind of thing.
I'm not incredibly active in reporting, but that's a good reason to ignore the ignore function.
Ideally, if you're an active reporter and want to use the ignore function, you can report a few posts by a shitposter and then put that member on ignore. After that, you've done your part and the person is either going to get banned or they're not. It wouldn't make sense to keep reporting their posts if the mods aren't going to take action.