Making a yeast starter can do a lot of good things for your beer. The biggest benefit you get from a starter is proper pitching rates. If you pitch the proper amount of healthy yeast you will make a higher quality product than otherwise.
Saving yeast combined with making yeast starters can pretty much replace buying smack packs after a while. I'm not sure what prices are around you, but that means I am saving $7 a batch, and around $30 a month. For me, the savings alone are worth it. Not to mention if you have the capability, then why not?