General anesthesia or IV sedation for kid's tooth filling?

Hey, my 4-year-old DD has three deep cavities in her front teeth. We went to a dental clinic in Edmonton, the place and service were pretty good. Unlike other dentistries, they don't care if parents accompany their child in the consulting room, that's great actually, for that particular reason I'm going to recommend them to everyone out there!
After a thorough check-up, the dentist said they usually try not to sedate kids for small cavity fillings! But in my DD's case, cavities are a little deep, so she needs to be sedated to get them filled! They referred us to nearby sedation dentistry, I have gone through their website, and things seem to be impressive! We got an appointment the next week!
But I'm confused, does a tooth filling hurts that much, because I'm not getting the point of anesthesia for just filling a tooth!
My DD is a very cooperative kid, so if the pain is bearable, I don't prefer her to be sedated! Any insight fellas? Anyone here has kids' dental sedation stories to share, preferably positive stories to ease my mind.
Thanks in advance.