They want the viewing figures so it doesn’t make any sense to fiddle the vote. The best way to gauge the most popular campmates is via the voting system. By kicking out the least popular members one by one day by day they should, in theory, keep the viewing high to the end.
It’s not a show like The Traitors or X Factor though. It’s less about who wins and more about how a bunch of people interact for 3 weeks outside of a normal environment.