My experience was that most people who ripped through the proofs were subseqently completely lost when they had to actually implement things in C later. They are different skills, and downplaying the importance of implementing on real hardware and programming languages and under real conditions does a disservice.

For instance, I recall my professor being wired up about some esoteric sorting algorithm, that had better asymptotic performance than qsort. Except, the constant factors involved in a real implementation made it slower for anything but stupidly big datasets. We spent like a week going over that one...