If, for example, you have a $1MM portfolio invested in a broad market index fund that generates 2% annually in dividends, that's $20,000. The standard deduction for MFJ is $24,000, so you would have zero federal income tax liability. For a couple, you need to have at least $23,335 in income to qualify for an ACA insurance plan instead of getting dumped into Medicaid (or worse, left out in the cold if you're in a state that didn't expand Medicaid).
Is your portfolio substantially larger than $1MM? Or do you have other sources of income? In either of those cases, I could see that you might need to worry about greater tax efficiency than you get from a garden variety index fund.
Edit: I forgot about the 0% tax bracket. The 0% tax bracket for qualified dividends and LT capital gains goes up to 78,750 for MFJ. So your portfolio would need to generate over 102k in capital gains and dividends (78,750 plus 24,000 standard deduction) before you would owe any federal income tax (assuming no other income sources).