Speaking for myself I can't say I remember "going ga ga" as such, but I was certainly intrigued when I first discovered it because it produces cool results with

Speaking for myself I can't say I remember "going ga ga" as such, but I was certainly intrigued when I first discovered it because it produces cool results with a form of machine learning that is under-utilised, based on combinatorial optimisation (at least the initial version as far as I remember extracts constraints automatically from an image, so it learns a model of how parts of the image can combine). The "wave function collapse" name is ... a little grandiloquent, to be fair. I personally haven't used it for procedural generation and I don't expect to but it has been used in at least two games I know of: Townscaper and Bad North. Combinatorial optimisation is not cheap but if it's good enough to generate game levels for simple games then it's not that bad. (Bad North does take a bit of time to generate a level, to be fair).