Currently the design is so that you don't clog up the function list for actions with loads of unwanted functions that are only used as expressions.
Can you put all these functions under another group - "Functions that return value"? In a large project the list of functions can already be quite long, so adding another group will not do any harm.
This change will make C3 functions a bit more flexible. Also, this is a commonly used functionality in other languages, so there will be no reason to remove it in the future.