It doesn't fix the spoiler effect (it makes its own version of it: https://en.wikipedia.org/wiki/Center_squeeze ), and it removes monotonicity. The second one is a big deal for me, at least in FPTP a vote for a candidate always helps them. With RCV, a vote for a candidate can hurt them, and sometimes not voting makes the outcome you want more likely than if you did vote for it.

The 2022 Alaska election was a great example of it failing: https://realrcv.equal.vote/alaska22/ FairVote called that election a success because people managed to fill in their ballots, even if they didn't get the outcome they thought they were voting for.