My 8 year old daughter is on the spectrum (diagnosed level 1; normal IQ in the 110ish range), and the diagnosis has helped us get intensive in-school support. She's doing well academically, but needs support in writing and social skills. Her diagnosis was essential to getting her the help she needs.

I also highly recommend living in a place with a decent school system and a well staffed special education department. Without that, my daughter would be floundering academically and socially isolated.