Believe it or not, I totally get you, because I never expected the drawbacks either (until I started editing for a living).
I don’t feel like it’s “boring” so much as the fact that it can be tedious. (Very fine distinction, I know.) Before I started doing this for a living, I assumed that editing was like reading and that therefore it could be enjoyable, entertaining, and conducive to “flow.” It can be like that — and even when a text is difficult, it can still be enjoyable because of the way the writer communicates, or because the ideas themselves are fascinating… but most of the time, it’s the sort of work that can only be enjoyable in very small doses… and clients’ deadlines don’t generally allow for a pace of very small doses. :-/
I’d still recommend trying it, though, for anyone who loves writing and has an interest in editing!