Every time this trips me up, it’s hand written SQL, because literally every other language I routinely use supports trailing commas.
The additional complexity during codegen is barely existent. If you’re using an orm or code generator this will be an issue once at most (if and when you write your own).
From my experience there are a lot of programmers that simply don't write SQL at all. They use an ORM or some query building library in their preferred programming language. So they're the ones that don't understand the problem when handwriting SQL, because they simply don't do it. Even the parent comment here is talking about PHP array syntax instead of SQL.
I write all of my queries directly in SQL, and I run into the trailing comma issue somewhat frequently. It's a minor annoyance, but I've just been dealing with it forever and accepted it.
Great contribution, thanks for nothing.