[reinman]

Crafting is particularly useful in testing

For example, suppose you just need to isolate and test a function but you won't want to manually write a test harness

A crafting system could build the upstream dependencies and then deliver you the results - no code changes needed

[reinman]

Yes anything that says "Functional Programming" in the title tends to attract a certain type of developer tackling a certain type of problem, usually program verification etc.

Not mainstream programming for sure