In all probability this name is just part of the background for those who see it every day. However this particular sandwich chain does not exist in Australia, so to my Antipodean eyes the name (if not the sandwiches) was fresh and a little bit clever.
Obviously this is a play on the French expression " Prêt à porter", meaning "ready to wear". Though admittedly I only got the joke because the verb is a variation of mangiare, the Italian for "to eat".
Well, I thought it was amusing anyway.