Let me see:
It gives you something to look forward to when they race.
You can travel to see them race and at the barn if you don't race locally.
Tax write off.
Actually speak with your trainer on the phone/see them when you travel.
Actually have lunch with your trainer after a day at the barn if you're there.
Actually meet other owners, grooms, trainers so you can learn the game better.
Maybe get some 'inside information' so you can hopefully make $$$$ at the windows.
i'm sure I missed a few things.