With so many optional calls being made in the NFL now, I wouldn't be surprised if the home field advantages are prone to be increased from a 3-point advantage to more than that in due time for the Vegas bookies to determine a more representative number.
The NFL really seems to be going all-out to make home team attendance noticeably more attractive to their patrons. It appears there's nothing like flagging the visiting teams to ensure as much.
Obviously, visiting teams are now obliged to overcome more penalties than they've ever had to in the past. Home field advantage is currently far more advantageous than ever. It's tougher than ever before on the visitors and their fans these days, no doubt!