Antoine must have had some difficulties because he said,
He who would travel happily must travel light."
He probably had problems lugging huge suitcases around — perhaps he went to Venice and found out too late that he had to take his bags onto the Vaporetto and then through the streets in order to reach his hotel room — or he was charged additional fees because his bags exceeded the weight limit, but, for whatever reason, St Exupery is correct. Take minimal clothing when traveling. One can always wash things in the bathroom sink and leave them to dry overnight. No one cares about what travelers are wearing (except at religious sights), so don’t expect to look as spiffy as the locals. Just wear what’s comfortable.
I have a bad habit of bringing lots of travel books with me, which are very heavy and bulky. My new resolution is to transfer important information to pieces of paper and leave the books at home.