Thanks for creating this topic, @DanThomas. It's incredible how much power there can be with very simple macros.
Another action that comes to mind is Trigger Macro by Name:
Yes, three big cheers for Paste by Name !
For those that might be interested, I've shared a generalized macro named Augment or Transform Text that so happens to cover the variable conversions. Of all the macros that I've created, I'm sure it's on my top five used list.