Some cruise lines do give more credit for higher cabin categories. I think Celebrity does, and Princess has started giving 2 points for paid suite passengers. Of course, with those like Princess that count number of cruises as their method towards tiers, people who can take those short coastals get an advantage that way (Princess does also allow number of days now too, but for day count suite passengers don't get any more credit, so you're more likely to get it on number of cruises).