I personally think of a transpiler as a transliteration compiler. Say my favorite language is scala but I want to write a neovim plugin which must be written in lua. I can write a compiler that transliterates scala

  val greet = (whom: String) => print(s"Hello, $whom!")

to lua

  local greet = function(whom) print("Hello, " .. whom .. "!") end  

I think this is a perfectly reasonable thing to do and it is very straightforward to implement for cases like this in which one truly is just doing syntactic rewrites with no analysis. If I had such a transpiler, I could write new code using my preferred syntax but transpiling to the host language. My project collaborators don't even have to know that this is my process. Writing a transpiler is also a great way to learn a new language since you are forced to learn the language constructs from the bottom up.

I do agree with the author though that usually you want to do more than just direct syntactic rewrites. But if you first write a transpiler, then you can extend it to do additional analysis but reuse the code generation components.