From what I see on the street, lots of people do use vintage road bikes to commute, but you should choose your ride with an eye for utility rather than what's cool or cheap.
A few cautions, steel rims are scary in the rain and 27" tires can hard to find so a bike with 700C wheels and aluminum rims is a better choice. Also parts and tools for 70s French bikes are rare and expensive so a bike with Suntour, Shimano or Campagnolo is easier to keep running. First and foremost, makes sure the bike fits you and your riding style, because if it hurts to ride you won't ride it and you have wasted your money.