For some of us, if we only trained no-gi we would only get to train once maybe twice per week because of a lack of nogi classes. Plus there are a LOT more comps available to us if doing gi too. It is all Jiu jitsu so it's all good. :-)
I refuse to put the gi, which has been very little as it is, on again until I get my nogi black belt. Im sick of the whole you have to wear the gi to be any good argument so we'll see about that.