It depends. When "a friend" got a ticket in SF the lawyer from a company, who probably plays golf with the judge, went instead of "a friend" and changed it from speeding ticket to "blocking intersection" with slightly higher fine, but none point violation. "A friend" got a feeling it's a regular thing. Which kind of of shows the scam the city is running.
"A friend" used another service for speeding ticket on HW9. They wrote a written declaration that looked like it made sense. The officer never replied, so can't tell if it was good or not.
Bottom line is you can do all of this yourself. The question is how much your time is worth, and how good you are at writing and knowing the law. As someone who sat in a one or two traffic courts I can tell you most people incriminate themselves within 5 minutes of opening their mouths. Also if "judge" sees you are not a lawyer they try to steam roll through you.