Yes, you can be the life of the party. Imagine the level of quality you'll get for $2 and the degree to which the sideburns or mustache will match your hair. Especially if you act like you're serious. Har!
Actually, this 1968 ad may have been aimed at the weekend hippies, whether students or office drones who were forbidden facial hair. But it seems to me that the only real practical use for these items would be as disposable disguises when robbing liquor stores ("He had these cheap brown sideburns and goatee glued on, officer...")