To be fair you can do all that without being DFed if you're careful (and maybe a bit lucky).
The only reasons for being DFed that I can think of would be to separate yourself completely from association with a morally bankrupt organization, for a sense of closure and to eliminate pesky guilt-tripping and manipulative contact from cultists.
The reasons to leave in general, on the other hand, are vast and innumerable. You can live a life of integrity, intellectual honesty, and freedom. You can give and receive true unconditional love. You can have open discussions about religion and philosophy without being careful not to step across some doctrinal line. You can live on your own terms and learn to be happy (whatever that means for you) without unnecessary feelings of guilt, fear and obligation being constantly pushed upon you.