Sure thing! It's on my list of things to do, so I'll use your ticket to implement. To manage your expectations, I'm busy with work for the next week but will start as soon as I can after that.
My plan was to make this customisable for the tooltip values, as they currently derive from the y-axis (or measure) and they need to be decoupled.
Can you confirm if there are any other specific parts of the visual that would benefit from configurable formats in a similar way? I'll do my best to include them here.
This issue will be resolved as follows:
Here's an example of the new output: