Most people cut the eggs just to see what's in there. It does make it a bit easier for the babies to get out, but they can do it on their own most of the time. If one of the hatchlings is having trouble getting out, some people cut the egg then to give him/her a hand.
I cut to prevent issues such as drowning or issues with twisted umbilical, I cut at day 52, I do not cut by curiosity if I wanted to know that bad what was in there I would cut a lot earlier than that but I don't.
Is cutting for everyone? No, it's one of those things where you need to weigh the pros and cons and decide for yourself and of course being knowledgeable on the subject is recommended.
To me as a breeder it's all about putting all the chances on my side, which is why I also chose to incubate the eggs in an incubator rather than let the female do it.