Bubbles imply misallocation of real resources as well as financial resources.
Both reduce efficiency. Perhaps more should be invested to reduce poverty. A bubble, by definition, means prices not justified by fundamentals such as consumer preferences and asset income. These did not change enough to justify the run up in property prices in Japan in the late 1980's, for example. Pat Hendershott has several papers arguing that commercial property markets must eventually return to prices based on investment fundamentals.