Why was it gotten rid of and what do I do with my cards that have it?
Make coasters
Put them in your bike tire spokes so they make it sound like a motorbike! VROOM!
In all seriousness, banding wasn't very fun to play with or against and got very confusing at times. WOTC stopped using it a while ago and I'm fairly sure you'll never see it again, besides cards like {Old Fogey}.
I still use them from time to time. They really tick-off the newer players. Team them up with a creature that has {Ghostly Possession} on it and your opponent will have a fit.