Real life examples.
My cousin struggled academically. My Uncle bought a cool car (Nova SS, sweet car for the time) and said my cousin could have it if he managed to graduate from high school. Look at it as a white trash trust fund.
My cousin dropped out of HS, my Uncle sold the car and kept the money. Had my Uncle just given the car to my cousin, it would have lost any motivating power. Only through profound knuckleheadedness was my cousin able fail.
I've also attended college with multiple directionless slacker/stoner/hippy-dippy types that were just burning through their college funds to no purpose. Many went on to drop out, pop out some bastards and get a dead-end job. They might have done better with parents who had the ability to say, "I'm not paying for an art degree so you can be a paper mache hack."
My sister has some great kids, but one is breathing up good air, and is destined for fail sauce. No reason to hand him a chunk of change to squander.
If you have the money invested in your name, and the kid is awesome...help them out. Pay for grad school, get them a car, get them a starter home, pay for a nice wedding. Nothing is stopping you. But, if you just outright invest in a kid's name...someday they can tell you to FOAD and go spend your money on gender reassignment surgery and facial tattoos.
Not every kid raised in a loving, supportive home turns out to be awesome and responsible. Most do, but bad apples happen.