Is Shikamaru useless?

[Suigetsu13]

As I recall he used a light thing once on tayuya to extend it. So I'm guessing he needs enough light to cast a shadow.

 

[Wik]

If I haven't missunderstood the jutsu it would work with any shadow including a shadow from an exploding tag or a torch or whatever. So I'd say he'd be more limited at night time but still far from useless. and ofc as many has said. Shikarmarus shadows are not that good. He could be just as useful just being there telling people what to do.