Advantage, benefit or blessing (4)
I believe the answer is:
boon
I believe this clue is a double definition.
'advantage' is the first definition.
(both can mean a benefit or asset)
'benefit or blessing' is the second definition.
(I've seen this in another clue)
(Other definitions for boon that I've seen before include "Blessing, favour" , "Benefit and advantage" , "Blessing - sort of companion?" , "A benefit, goes with blessing" , "Beneficial thing" .)