You can't say that mock papers are very important for IBPS exam but yes, it will definitely help you to score good marks. As we all are aware of the phrase that: "Practice makes a man perfect" and test series is a way to get acknowledge yourself as well as to do practice. So if you give time to test series then you will get better marks. However notes is also important but the thing is after completing notes and getting all the concepts clearly, you can solve test series at last.

Good luck! 

Yes It is suggested that mock test series prepare one well for the exam. If you give 2 to 3 mocks daily and also analyse it properly your score will definately increase. 

Furthermore it is upto you to decide what is best for you.

All the best

Its, upto your wish and your preparation, they wouldn't do you any loss, they would benifit you in one sense or the other.