It’s very nice to see that X people liked a post/comment and Y people disliked it instead of just having a singular “goodness/badness” rating. It (literally, in a mathematical sense) adds a whole new dimension to post ratings and gives us a more nuanced understanding of people’s opinions. Plus, it feels a lot better to see that 5 people agreed with you and 7 disagreed when you made a controversial statement instead of just seeing a score of -1 telling you how bad you are.
I think it’s totally fine to have the option, personally I find it the “goodness/badness” percentage to be more appropriate. A post could have 1000 upvotes with 5 down and I’d only look at the 5 and think “wow, so many disliked this” where it’s actually 99.5% positive.