GAT Subject Tests are meant to test your knowledge and skill level in a particular subject area. These subject tests are emphasized by undergraduate programs.
Not every graduate program asks you for a GAT Subject Test. So make sure that the program which you have chosen asks you to take the desired GAT Subject Test. Specially, for M.Phil programs many universities demand GAT subject score for applicant's evaluation.
Many a times if you are opting for a program outside your undergraduate major subject then you may need to take corresponding GAT subject test.
