I'm pretty convinced, you can do crazy stuff with JSONata as well. People don't do this (usually) not because they're unfamiliar with JSONata, but because it's crazy stuff. On the other hand it feels very convenient to write a small function to process a value in-line within a change node.
Not sure yet that I get your point regarding documentation. Of course there's the standard JS editor opening when you press the ... button. Agreed, the script doesn't look too nice in the small input box - as does a JSON structure or longer JSONata statement. Once we've clarified the 'if', there'll be time to investigate the best way to represent things...
Functionality can always be discussed. Yet ... why shouldn't that be possible and helpful?
