The big one, in most cases, is the employer match on 401k. You can get 100% growth on day one in a 401k plan that you cannot get in a Roth, if your employer offers a 1:1 match on some portion of your savings.
Yes, the 401K is idfferent altogether, because of salary limits, matching contributions, mandatory withdrawels, Roth options within the 401K etc. But bet. the Roth and traditional IRA, isn't it true that you get all of the earning tax free? Or do you somehow have to pay taxes on the growth?
Consider a hypothetical example, where we put $19k into either a Roth or a Traditional. Assume a flat tax rate of 15%, and a 30-year growth of 300%.
Roth: Start with $19k.
Pay 15% tax: you now have $16,150
Earn 300% over 30 years. You now have $48,450
Take your money out, tax free. Final score: $48,450
Traditional:
Start with $19k.
Earn 300% over 30 years. You now have $57,000.
Take it out and pay 15% tax. You now have $48,450.
Did you spot the difference? Here it is: with the Traditional option, you maxed out the contribution, but not with the Roth. You only put $16,150 in a tax deferred account, although the limit was much higher. You could have crammed even more money into the Roth to grow tax-advantaged.
Once again but this time start with $22k:
Roth: Start with $22k.
Pay 15% tax: you now have $18,700
Earn 300% over 30 years. You now have $56,100
Take your money out, tax free. Final score: $56,100
Traditional:Start with $22k.
Put $19,000 in the IRA, pay tax on $3k, and put $2550 in a taxable account.
Earn 300% over 30 years. You now have $57,000, in the IRA, and $7650 outside.
Take it all out and pay 15% tax, plus 15% on the gain in the taxable account.
You now have $48,450 from the IRA, and $6885 in the taxable account.
Total: $55,335