We do assess all of those things. Again: you're a professional. We give you a work sample test. You look at it, and use your best professional judgement to decide if it is (a) reasonable and (b) doable in the budgeted time given your capabilities. If either is untrue, you don't do the work sample.

I'm having a real hard time seeing how this isn't strictly better than an interview, which, as the article (and basically everything written in the last year about interviews) points out, is basically a random function.