Yes. Practicum is an important training session for new trainee teachers to experience what is in the real teaching 'world' so as to perform better in their teaching expeditions. It is the best way to know the true state of affairs in the field of teaching; the platform to bring to life the theories taught students in their training.
Yes it helps a lot. Through the practicum training the trainee teachers will get ample information, experiences and technologies that will practically help them in their future endeavors. But the most important thing is the trainees ability to that contribute a lot to be a good and exemplary teacher in coming times.