First-past-the-post is very good for the top two parties. It gives them a monopoly on election success, and prevents those irritating third parties from winning elections or influencing the major parties. It is better because instead of just choosing a single candidate on the ballot, you can choose as many as you want. After that, the election just goes to the candidate with the most ballots where they were chosen. This can either be a plurality or a majority. Through first-past-the-post, it is also impossible to game because the ranked choice system can be gamed in a couple of ways to prevent the preferred candidate from winning.
In conclusion, it is better because it also could be the death knell for partisan politics. The reason why you have a two-party system is that using first-past-the-post forces you to be behind one candidate, otherwise you split support. If all the qualified candidates could run at once, you could do away with primaries and it’s less likely extremists on either end could win a general election.