Sometimes single line functions and handlebars are not enough, but the problem is too small for a full on code block. Like for example a phone number conversion script, or a first letter of name capitalizer. These things require a short function maybe 5 lines long and are annoying to implement as function blocks. I would rather a little switch and to turn the expression block into a code block with a return statement.
This is above my programming level. I would work on it if I could, happy to pair program on it though!