> "free" space being contextualised isn't entirely nice. better to be clear how its consumed, than say its free.

I would guess that for more than 99% of users just saying "free" about swap/temp is the best option and it would just be confusing to say less disk is free or show multiple values. And if you really want to know you can just select "Get info" on the hard drive and see how much purgeable space you have.

Having really good background processes that makes sure the space is free when you need it and easy to understand error messages when it can't purge is of course great for everyone.