I've not directly experienced it, but I have some idea. My impression -- I'm not sure how accurate this is -- is that if it looked useful, it would be socially accepted more or less, but if it just looks for fun, it wouldn't be (obviously you can't really tell, of course). That is some people would just rag on you anyway, but that many people would be shocked you might simply be interested, but eg. if you were an academic, or doing an open-u course for mild career benefit, or something, they'd be surprised but sympathetic.

Dad told a story about a friend of his who was walking the coast of America. He said people were generally flabbergasted and even hostile that he would, just because. But when he started telling people it was for a bet, they were all smiles.