If you want do decrease the degree of coupling to a certain orm tool, then jpa is a good choice.
It defines a set of well defined apis that you may use with any existing persistence provider.
Some projects require a specific persistence provider. Hence the jpa allows you to apply (not only) the basic orm mechanism even if you are not that familiar with the specific implementation. (I don’t recommend to use tools that you don’t know, but the jpa provides an abstraction an certainly lowers the entry barrier)
solved Advantage of using JPA [closed]