Anytime you put yourself infront of others, it really is not a waste. Our local used to do a New Realtor event, I was on the committe. It was a great time to network with other Realtors. Networking with other Realtors is very important, Its always easier when you know the person that is your opponent during a deal.
If you go to an event, eat the free food, drink your free drinks, and leave, its a waste of time. If you go to an event with the expectation of picking up a client, its a waste of time. Networking is about getting your name out, passing out a card, and building a relationship for FUTURE business.