I'm an agnostic who keeps my distance from self-proclaimed heretics inhabiting the modern-day Church of Github (which formed as an offshoot of the Cult of Git, which itself emerged after launching a savage religious war with the iconoclastic Sect of Subversion), who prefers to have
both a logical, reviewable commit history AND informational pull requests.
Smashing commit history via squash makes debugging harder. Provided you have the interactive rebase chops to pull off crafting a decent granular history, you'll reap significant dividends down the road if you keep that history intact. Because it's right there for you to use with `git blame`, etc.
And then why not have proper discussions in the pull request with reviewers? Sometimes important stuff comes up in review. Sometimes you might close the PR and start anew. Sometimes the PR gets incredibly lengthy. Maybe the result is a commit history which condenses some abominably lengthy PR.
There's no need to choose between them. You can have both!