Talk to Gynecologist on Gynecologist

AOA, My sister 31, delivered her first Baby, weighing 2.8 kg (at the time of birth). She got a normal delivery, but was induced artificially. She got a vaginal cut by her doctor at the time of delivery. Its taking time to heal up, and i know it will take time. But i want to know, why it is a trend now a days to give a vaginal cut? Although baby was not too big/healthy, it was just 2.8 kg. And i have seen so many cases of vaginal cut in my friends and family, while babies were not too big. Please guide me is it really a need?