Crowd-based Requirements Engineering, or CrowdRE, is an emerging requirements engineering paradigm in which a crowd of users plays a central role in carrying out activities such as elicitation and prioritization. In this keynote, I analyze the value of CrowdRE, focusing on its effectiveness and impact in research and in practice. Starting from research carried out in collaboration with industrial partners, I make the case for the need of conducting in vivo research for CrowdRE. This type of research is crucial to gather evidence for the practical effectiveness and to ultimately establish CrowdRE as a prominent paradigm for the software industry.