Functional programming excels at succinctness, owing to the existence of higher level functions (map, lfold, grep) and type inference.
It is also excellent at generic programming, for the same reasons, and that further increases the ability to express complex ideas in a short statement without obfuscation.
I appreciate these properties since they make interactive programming plausible. (e.g. R, SML).
I suspect that functional programming can also be verified more readily that other programming approaches, which is advantageous in safety critical systems (Nuclear Power Stations and Medical Devices).