It's still a risk though on whether we will experience good things or bad things. For the majority of people, chances are, it will be a mixture. Although- does it really take much for the bad to outweigh the good? We may even contract mental illnesses where- no matter what happens- things seem so much worse than they are.
So sure- it could work out well. Someone may end up grateful they got the chance to experience all this. But- can they feel annoyed or, like they missed out if they didn't? If they don't exist, are they capable of feeling anything?
I guess that's why people argue that non existence is safest. In terms of numerical values- non existence could be seen as a zero score. Once we are born, we effectively start having positive, plus experiences or, negative minus ones. With no way to definitely prevent the minus scores- is it truly a gift? Did it have only good intentions behind it even? It could potentially be a box of poisonous snakes.
