The combine tells you nothing that the interview won't tell you. If you do the combine, you still have to do the interview. There just aren't enough points for both. I'd rather do the group workout, and after that, get as many interviews in as possible.
As for people trying to "cash in" on points error, I don't agree. When I spent $40k a week scouting and the system told me I had X points, I assumed it was correct and proceeded accordingly. Then more than half those points disappear and I'm sitting with no interviews done. I assume I get more points between now and the end of the season, but without the combine, I could have done 5 interviews.