Ironically my objection to this service is essentially the opposite of yours. I see this app as imposing a middleman's fee on something that, in a perfect world, citizens would be able to perform themselves with the same probability of success. Contesting an illegitimate parking or speeding ticket is a fairly straightforward matter, but in my (personal) experience, unless you bring a lawyer to the courtroom your arguments will simply be ignored. In my area, the courts do not even keep records, so you can't use the judge's blatant dismissal of your concerns* as grounds for a mistrial on appeal.
Maybe I'm not understanding how the service works, but I see this service as simply a specialized and cheaper lawyer replacement. Maybe that's progress since you can actually save some money if you win, but you're still paying a more powerful entity in order to get respect in a court of law.
*I've literally been told by a judge, "stop speaking now, your turn is over" seconds after showing that the officer didn't use a LIDAR gun correctly per the manual, and upon cross examination didn't even know the type of device he was using (Me: "Were you using a radar or a laser based device on <date> at <time>?" Officer: "I was using the device the department issued me." Right afterwards: "Me: If you don't know what kind of device you were using, how can you know the effective range of the device?" Officer: "I believe it was effective and accurate when I used it."). The judge repeatedly referred to it as a "LASAR" device...