When I write first drafts of briefs, articles, etc., I almost invariably use italics for particular words or phrases that I want to emphasize. Not many bolds (and no exclamation marks), but italics, yeah. I do that.
But when I get to second and third drafts, I try to take most of them out. Not all of them. But most of them. Because, yes, I felt strongly about 'em at the time, and thought they helped the reader to understand the point (and the emphasis). But usually, they're more distracting than helpful. So at least in academic and advocacy pieces, I try to use emphases somewhat sparingly. On the theory that readers generally don't appreciate them nearly as much as I do.
But maybe I'd do something differently for Justice Gilbert.
There are a lot of italics in this opinion. At lot of words and phrases that get emphases. Pretty much one or two every page.
They don't bother me at all. In fact, I think they help identify his point. I concede that they may make the opinion read a bit more, say, aggressive than a mere neutral explication of legal principles. But that's okay. At least for me.
Maybe Justice Gilbert prefers writing italics to reading them, in which case I should keep to my usual practice.
But I can honestly say that I was struck by how many words and phrases were italicized in this opinion. Not what you usually read.