it's pretty simple. Make sure you aren't thinking it's a complex idea.
Suppose you want Ross Perot like I did in whatever year that was with the three major candidates. Suppose you do NOT want Bill Clinton, so your acceptable second choice is Bush. But you don't get a second choice, and (IMO) the votes that Perot gets are drawn off the votes that Bush would have gotten, resulting in a Clinton victory with less than half of the popular vote.. In other words, I screwed myself by voting for who I wanted. But if I was able to rank choices, I and many others like me would have succeeded in seeing Bush elected (a Perot victory was unrealistic but still, he secured a big chunk of the popular vote).
So a ranked choice vote represents a chance for the will of the people to not get shanghaied by voting your preference. It's lunacy for a Bill Clinton to get elected when the majority of people wanted either Ross Perot or George H.W. Bush. So there's that but there's more.
Now, Ross Perot's candidacy isn't just a monkey wrench in the works, it's given credence and allowed to grow into something more significant, rather than being seen as at best a wasted vote.
With his (Perot's) political presence now meaning something, the other parties must pay attention to what the attraction is, and adjust their philosophies accordingly, again forcing elections to favor the will of the people. And who knows, his party might coalesce with another to form a better, more representative party that is responsive to the voters and not so much to the quest to remain in power.