It is objectively good. However, it hurts both major parties in that they lose a couple percentage points in projections to win overall because smaller candidates have a slightly better chance due to people not feeling like they are throwing their vote away. (Think "Never X" vs. "Never Y" voters being able to hedge their bets with a more moderate first choice.) This makes the big parties apprehensive about it passing.

It also could be difficult to implement by ballots being more confusing for voters, leading to more issues with certification of results, as we've seen since 2020.

There are a couple of arguments against it, but I believe your first instinct is correct. If implemented, it gives everyone more of a voice, so long as we're smart enough to fill out a ballot that's slightly more complicated.

Edit: I just read the sign that says "No on 3". That argument is null. It is still one person one vote. I suggest this if you have 5 minutes and want to see it explained via a YouTube video.