Hello dear

It is not like that ; if you donot give any mock test than you will not crack BITSAT.

You can do without this also; but if you have aware and habitual of the test pressure and silly mistakes we done during exam and time management and surrounding and other factor  than it will help you in exam and youwill score more marks .

As BITSAT exam is somewhat speed booster test ( you need to manage your time and speed ) and it check your basic conceptual and subject knowledge.

So I would suggest to practice those mock .

Good luck.