“Taxpayer's income is less than the Standard/Itemized deduction.”

That’s a good point, especially these days with the $6K/$12K “senior deduction.” I often tell clients to take IRA distributions to get their taxable income up to break-even. They can do that without a Roth conversion, though. If their tax bracket this year is below zero, it’s likely to remain there in the future, unless there are fluctuations because of (for example) capital gains.

“sometimes folks that are financially secure just want to get the conversion done so their kids don't have pay taxes on their IRAs”

Another good point. And sometimes parents are in a 10% tax bracket while the kids are paying 35%. Or parents live in Texas and kids live in California.  

And then there are the millionaires who want to reduce their estates below $14 million by paying income tax now to avoid estate tax later. Assuming it’s not going to be repealed before they die.

(Neither of these cases could be spotted by the Tax Planner feature that inspired my original comment on this subject.)  

Nevertheless, I suspect that 90% of the few who should be doing Roth conversions, won’t; and 90% of the many who are doing them, shouldn’t.