Sometimes it feels like the least-bad alternative.

e.g. I'm currently working on a substantial framework upgrade to a project - I've pulled every dependency/blocker out that could be done on its own and made separate PRs for them, but I'm still left with a number of logically independent commits that by their nature will not compile on their own. I could squash e.g. "Update core framework", "Fix for new syntax rules" and "Update to async methods without locking", but I don't know that reviewers and future code readers are better served by that.