My biggest worry (and I still have some of those other concerns) is for school-age children using it instead of having to learn how to read for information and to write in their own words.

For everyone who argues, "naysayers said that letting schoolchildren use calculators would ruin their minds, but it didn't," how many people do you know who can make a good estimate of their share of a restaurant bill without pulling out their phones? Think about how that translates to how well they grasp at a glance what they're getting themselves into with Klarna, car loans, etc.