Villager Token Description

When you give a token, you are contributing to the settlement of the Mayor you give it to.

The more tokens the Mayor receives, the greater the settlement becomes. Each token increases population and, at certain thresholds, tokens will create special Settlement Upgrades that your Mayor can use to increase the city limits, add additional buildings, and more!

They were designed as a way that villagers could gift them to their mayors and barons and help increase the settlement without just gifting EP.

Tldr. Yes they are useful for barons, but not useful to purchase for yourself as you could get EP instead.