My Club is very active on club wars and we have got 2600 club war score already. I don't know should I stop playing on club wars because it waste my resources and time and I don't know can the benefit from winning a club war can cover the resource I lose from gathering war items.
I cannot say this is a total waste of resource and time.
If you win a club wars you can get 10-50 simcash and this is a very big amount. You can also win many gold keys too.
If you ask me about a waste of time, yes. This is because you need to keep produce resources to make war items and you need to keep track on the war supplies very carefully.