For a change small enough to fit in one commit, that works. For a larger merge, you might still want multiple commits merged together. For example "make the foobar extensible" and "extend the foobar to add the baz" are really two separate changes that may be merged as part of a single PR to add the baz.
“make the foobar extensible” has no value without also “adding baz”. If I need to remove baz, I can’t just revert “adding baz”. The extensible foobar needs to go as well because it’s a unused abstraction.
