Fame
People know the horses—they don't know the jockeys. People know names like Secretariat and Seabiscuit. Who are the jockeys who rode these legendary horses? Most people couldn't care less.
You won't get famous on ESPN, but you might become famous in racing circles. If you're good and you consistently win races, you'll be well-known and respected within the community, and trainers may have you on speed dial.
Just don't expect to get chased around by the paparazzi, unless you're riding the horse down Sunset Blvd. Oh, and most of those "paparazzi" will actually be police, in that case. So maybe don't do the whole Sunset Blvd. thing.