The 21 Century Cures Act ("Cures Act") relies on the concept of real-world evidence ("RWE") to improve the Food and Drug Administration ("FDA") approval process. This has amplified interest and furthered momentum in applying RWE more broadly, beyond FDA regulation. In this article, we discuss the understandable appeal of RWE's pragmatic application and its many potential benefits. But we also caution that claims about RWE's wide-ranging, ameliorative impact on the health care system are likely overstated. The real world of RWE is messy and uncertain. Successfully incorporating RWE into regular health care system decision-making, beyond the FDA, faces considerable obstacles and limitations. We review the reasons to be wary about RWE as a game-changer. These concerns including data reliability, insufficient incentives for stakeholders to generate and engage with high-quality RWE, and lack of comprehensive regulatory oversight. In addition, the push for RWE may impact the enforcement of the health care fraud and abuse laws, perhaps not in necessarily positive ways. Increased reliance on RWE may have significant implications for off-label fraud enforcement, further conflating the distinction between claims that are false for reimbursement rather than for scientific purposes.