I think in many cases there is some degree of personal satisfaction in doing it yourself - within reason, and depending upon one's goals.
Here is before sanding/grinding - note the heavily cracked paint on the hood; it was all over (pic was for the fender in another thread)
Before anything Here is after my grinding/sanding work, but before primer:
Before and here is after primer:
After and I can look at it and say yeah, I did it and it came out nice.