Of course just because there are technically flaws, doesn't mean it's not an improvement over the status quo.
Instant Runoff Ranked ballots are particularly well suited for electing a single position like a Mayor or President. Given that it's still a majoritarian system like First Pass the Post, it's a much more questionable system to use for other things like electing a parliament.
I remember seeing a 2D chart representing voter preferences on the X and Y axis, coloured by who wins under those preferences (and some symmetry-breaking assumptions). Some systems showed clear biases towards certain outcomes. IRV had a pretty symmetric shape but with a splotch in the middle that was a random jumble of different colours - an unpredictable, chaotic outcome.
The problem IMO is when there's better options but it's hard to get people to care enough to switch systems again. I'm hoping Ranked Robin can catch on so at least places that went to IRV can switch to a better system without new ballots.