529 for kids- for or against?

What is the best reason to, or not to start a 529 for a child? I was planning on doing a 529 for my newborn, but I originally thought they were tax deductible at the federal level, and turns out they aren’t. So it appears the only benefit is withdrawing the investments and not paying long term capital gains? Any reasons not to do it? Ie- -would it lessen chance of getting financial aid or loans? (I likely won’t qualify for aid) -worse possible investment options than the market? - money tied up/lost if kid doesn’t go to college? Thanks for sharing any insight