I can imagine that it is the sort of thing that would make your career if you succeed and generate publicity even if you fail, since you’d have a pretty good excuse.
My understanding is that the system really requires that EVERYONE have the best defense possible; if they are truly guilty the truth will out, unless the cops/prosecutor made a mistake.
“Better to have 100 SKM’s or Mansons walk free than one innocent person be punished” as my lawyer friends put it.
I think you hit the nail on the head. Appearing in a widely publicized case is a time honored way to get advertisement. It used to be lawyers were forbidden to advertise so they would run for office, do pro bono work, take on a widely talked about matter etc.