If you want to take admission in M.E. or M.Pharm course which is offered by BITS then you need to undertake BITS HD exam and GATE is totally exempted and vice-versa. Hence, getting admission into BITS higher degree program, you have two ways: Either go for GATE or through BITS HD.
Although there are some pros to get through the gateway of GATE:
It is not at all necessary for you to get a rank in the GATE exam, for getting into BITS despite writing BITS HD. Although few changes have been made that you should consider before applying. BITS has introduced a system from 2018-19 to reserved 50% of its seats for admission through GATE candidates and the rest of 50% seats are reserved for student's admission through BITS HD.