Absolutely. If someone formulates their PR such that every commit in the chain is small, easily reviewable, and passes all tests, that's fantastic! That makes reviewing code, searching history, and bisecting all easier.

Unfortunately, that's not the 90% case that I see. Most of the time a multi-commit PR contains N-1 commits of incremental development and one final one that fixes all the tests and typos and removes debugging print statements. Neither the project nor the author benefit from having those intermediate commits integrated verbatim.