I've yet to encounter anything erected for no reason at all. But there are plenty of projects where rationality didn't have much a role in their choice of creation. Examples like that can usually be tied to a previous dev/engineer wanting to pad their resume with a new project, maybe with a new framework. Or a manager who wanted their team to have more completed work to look better on some miscalculated performance metric. Failing those options - it could be a bored employee who just wanted to make _something_.

That is to say - most people are acting rationally, but their context to an outsider may not appear rational. Maybe there's something to be said for a general relativity of rationality?