I have nothing against semicolons. Or em dashes. Or parentheses or exclamation points or colons. And yet when editing, I remove them. I boot them right out of the story.
Not all of them, of course. But the thing is, it’s easy to overuse punctuation marks. Semicolons and em dashes stand out precisely because they aren’t meant to show up in every sentence. Too many of them at once and they clutter up the page, distracting the reader. (And parentheticals are supposed to convey information that’s additional to the main point that the writer is trying to convey, so it’s awkward to introduce something in parentheses and then use it in the main body of the text as though it were there all along. Yes, I’m being meta.)
Any punctuation that gets overused begins to have the same effect as someone typing in all-caps all the time; it hurts the reader’s eyes and they stop reading. For a particular punctuation mark to have an effect, it needs to be used sparingly.
So think of it as weeding a garden. Leave the good marks in place and yank out the unnecessary, incorrect, or annoying ones. The result is cleaner, more graceful, and easier to read. Your reader will thank you.