Most people use pots due to the invasive nature of some herbs, like mint. Others use pots to move their plants around in their gardens to add interest or to chase the sun. Many Gardeners sink pots to keep the mounded shape of the plant for cosmetic reasons or to deter pests.
If you are new to herbs, stick with pots. It's awesome having moveable herbs to adorn & scent your living spaces, indoors & out!