Under RCV, a candidate must have both a depth and breadth of support. Depth is defined as 1st choice votes. You must stand for something to inspire enough passion in voters to vote for you 1st. If you do not get enough 1st choice votes as a candidate, you will end up being eliminated. Therefore, a milquetoast strategy to chase only 2nd or 3rd rankings could actually cost you the election.

Additionally, voters do not need to rank every candidate for their vote to count. They may just rank the candidates they like in order of preference, so an unappealing candidate still has to work for these votes.