If you want to improve your reading, go for it.  Big band stuff can be quite varied and a lot of the standards crop up in all kinds of gigs.  Some of the best work I've ever got was as a result of depping for people because I could read (and I was always rubbish at learning stuff).  It's also great discipline, and can help you realise where your technique is patchy! 
 
Good luck 
 
Mike