ANY exersize is better than NO exersize! Yeah, the bands aren't iron, but there's a principle at work here: the definition of exersize.
Exersize is activity above and beyond that to which you are presently accustomed to.
But that doesn't make you strong. Training does.
Training is exersizing consistently, and progressively.
Play with your bands if you want to. You might also look into BW exersizes, motel exersizes (bench the bed, curl the chair; DON'T try chins on the shower bar...) and in your case, an old bullworker would come in handy. I think they're still around...I saw some at Play it Again Sports, so they can be found used at least.