I guess as everything in life has two sides. If you'll like to start a professional barista career, than this might help you to get the food of the ground.
Next big question is what is the diploma you'll receive worth?
Do you need a diploma to get a job, and when you'll have a diploma how much more will they pay you. At least you'll having a great time, and be able to network with your co-students.
In the perfect world, a good school should have already a line of SC Shop Owners lottering around, and waiting for the next students to be released.
IMHO barista schools might help a bit, but what it really needs to be an outstanding barista are values that can't be taught. What I seek in a barista is excellent communication skills, a dedication to cleanness, a life time curiosity and always in pursuit the Godshot.