Looking at multiple commits is not a good workflow:

* It amounts to doing N code reviews at once rather than a few small reviews which can be done individually

* Github doesn't have any good UI to move between commits or to look at multiple at once. I have to find them, open them in separate tabs, etc.

* Github's overall UX for reviewing changes, quickly seeing a list of all comments, etc. is just awful. Gerrit is miles ahead. Microsoft's internal tooling was better 16 years ago.

* The more commits you have to read through at once the harder it is to keep track of the state of things.