I think this part of her essay is important too.

"A defining element of DT>PI was that students must not just study what is the next logical step in a course, but they must through the exhortations of a teacher or professor attempt to go beyond what was thought statistically possible — they must stretch themselves intellectually at every point. Professor Stanley used to constantly quote the line of the poet Robert Browning that one’s reach must always exceed one’s grasp. . . .

So while I am delighted that self-paced education in the form of adaptive and competency-based learning is finally a more generally discussed component of reform in American education, I urge that those advancing it think long and hard about some of the humanly-damaging consequences of learning platforms so perfected by technology that students are offered a Faustian bargain – the comfort of non-resistant and frustration-free learning in exchange for the ultimate loss of a resilience needed for a satisfying life after schooling."

I know my perfectionist DD would cruise along at a pace that let's her show her mastery without tackling material that really challenges her unless I worked with her teachers and used diagnostic testing tools in online programs to make sure she was appropriately challenged.