Last year I took a seasonal cashier job at a chain hobby store, just "for fun". I loved it - lots of chatter with customers about their projects, a big employee discount weekend, and I enjoyed just getting out of the house. Easy work & no stress when I left at the end of the day (usually 4 hour shifts). They asked me to stay on, but I decided not to because of some family health issues that popped up. I may do it again., but it's really nice to have the choice.
I know for a fact that I was just as fast as the 20 year-olds, and had some customers who told me they loved my attitude. One regular customer said I was the best cashier in the store, LOL. More than once, after ringing up a purchase, the customer changed the amount of cash she handed over and I had to figure out the change in my head. They laughed that I was able to figure it out, as many younger employees just can't do it. So yes, I think the older generation has a leg up for some of these jobs, if they want them!
On a side, perhaps political note, there is lots of talk here in Maryland and elsewhere (ex: fast food employees) about raising the minimum wage from $7.25 to $10.10 or more because "people can't live on minimum wage." I truly believe that some of them are shooting themselves in the foot, because if the minimum wage goes up that high, you might find more people like me finding it worthwhile to take that part time job. You'll get better workers, and some of the people who think they "deserve" more money for poor work will find themselves out on the street.