I'll say it again since I've said it a million times, it can be useful and a bubble. The logic of investors before the last market crash was something like "houses are useful, so no amount of hype around the housing market could be a bubble"

Or, quite similarly, the internet bubble of the large ‘90s

Very obviously the internet is useful, and has radically changed our lives. Also obviously, most of the high stock valuations of the ‘90s didn’t pan out.