530(A): 5k a year up for next 18 years, for 5 million in Roth for kids 60 years from now? What am I missing?

If you've got excess money to invest that you don't need for 18 years and you ultimately want to give that money to your children, then ... **Don't we need to give 530(A)s more credit than they're currently getting if the plan is to convert to kid's Roth IRA?** Isn't this correct: - Contribute 5k (post tax) a year from now until child is 18 - At age 18, that's about 90k in investment and 60k in returns, so about 150k, and convert to Roth - Then one of two things happen: either (A) you wait until 25 to avoid kiddie tax otherwise you'll get hit with 60k in extra ordinary income, which is about 20k you owe on top of the 90k you've already spent or (B) if your child isn't in school and on their own then you avoid kiddie tax right? In either case, you avoided the tax, and they've got 150k in a Roth IRA at age 18, which is like 5 million tax free. It costs you like 100k to set up your kid for retirement. **Where am i getting things wrong?** I hate everything to do with the name of these accounts, but maybe they make sense? Let's say they are at the bottom of the investment priority list (behind 401ks, IRAs, 529s,) but aren't they better than brokerage accounts (and to a significant degree)? Also note that they could use the contributions in this account for a downpayment for a house. _______ Edit: Appreciate all the responses. Ultimately, we're all just figuring out how to save money, which isn't a bad thing. If you put this into AI here's what I get Net benefit 60 years from now of 530a over taxable brokerage assuming 10% annual returns after paying conversion tax at age 18 on 530a conversion (ira to roth ira) and assuming you avoid kiddie tax: Avoided capital gains tax $1.61M Avoided dividend tax drag $0.5–0.9M Gross tax benefit $2.1–2.5M Less conversion tax −$20k Net lifetime benefit ≈ $2.08–2.48 million If your child withdraws at 65: 3.38–3.88 million at 75: 5.4–6.2 million