The feedback in the article was obviously far from perfect, but from the sound of it, “good attempt” could be an actively harmful thing to say. Lots of effort had gone into making the wrong thing and making it fragile, which isn’t good at all, it’s bad. If you’d asked an employee to make a waterproof diving watch, and they came back with a mechanical clock made from sugar, even though it’s impressive that they managed to make a clock from sugar, it’s completely inappropriate as it’d stop working the instant it got wet. You wouldn’t want to encourage that kind of thing happening again by calling it good, and it’s incompatible enough with the brief that acknowledging it as an attempt to fit the brief is giving too much credit - someone who can do that kind of sugar work must know it’s sensitive to moisture.

The manager can apologise for not checking in sooner before so much time had been spent on something unsuitable and for failing to communicate the priorities properly, and acknowledge the effort and potential merit in another situation without implying it was good to sink time into something unfit for purpose without double checking something complicated was genuinely necessary.