Thanks for such a nuanced response (your note to commenters is also much appreciated)! I spend my days working on an adaptive tutoring product, which delivers a math curriculum through continuous assessment — the assesssment is baked in to the learning. The potential of these digital tools lies in their ability to automate the mundane, time-consuming tasks of setting and grading assignments. They are not a silver bullet, nor are they intended to supplant the role of the teacher. But designed and implemented with fidelity, they can free up teachers to spend more time on rich classroom activities and foster deeper learning experiences (which I agree PBL is great for).