Point differential tends to be a better indicator of where a team will end up in terms of overall record, and right now the Celts have the third best point differential in the conference, just a hair behind the Raptors.
It's true that beating bad teams isn't especially impressive, but absolutely demolishing them, historically, suggests that a team will finish with a good regular season record.
That said, it seems likely that having home court advantage will make a big difference against the Bucks, Raptors, and Sixers. The Celts still haven't shown enough to instill confidence that they'll be able to overtake the Raps or Bucks in terms of record.