[XorNot]

There are plenty of engineering projects which don't sound like a great idea, then turn out not to be a great idea [1].

(admittedly on that one I'm not really onboard with "oh lol why are we using wood for a bridge when we have steel" as an explanation, but conversely there were serious problems with engineering design of how wood was used on this bridge and it did collapse in the end - complexity of design versus known elements is an important consideration. A casual observation of "does this really make sense?" might've concluded that stepping so far out of bounds of normal design should have been more carefully treated or had exceptional requirements in the first place).

[1] https://en.wikipedia.org/wiki/Tretten_Bridge