Simple functions like `lt` are there because of the lack of currying in the language Javascript. They can improve readbility in other languages. I'm not sure why the example is using `R.lt(R.__, 3)` in the first place. If a curried version should be used, `R.gt(3)` is without the placeholder. If not, the lambda `x => x < 3` is fine. But often curried versions are nicer to read, e.g. `R.add(1)`.
I like this comment, where the author gives more details. E.g. that `gt`/`lt` implement `Ord`.
https://github.com/ramda/ramda/issues/2755#issuecomment-451745388