Having a Self Closing Gate Hinge on your garden perimeter is a great idea if fitted properly and your fencing is inline with the same type of security to prevent vermin or intruders of the mammalian kind invading your hard-worked garden.
Many a gardener has suffered losses in the garden because they either have a good protective fence but a gate that someone always forgets to close or a good self-closing gate but not a good protective barrier or fence, and that is how the unwanted guests get in and destroy your garden.
So the best is always to get a good quality fence that surrounds a garden in the center of your property that is dug out of a square or rectangle piece of ground to the size and depth you will need and fill with concrete and place your garden soil in that shape and a gate that will close on its own and thus leaving you garden safe from intruders.