The 'Movies' browser extension is an intrusive application carrying adware capabilities. More importantly, infosec researchers are warning that the application is part of the ChromeLoader malware family. Applications from this family could carry additional, invasive functions or even install more unwanted browser extensions on the device. Naturally, applications of this type are very rarely distributed through normal methods. Instead, their operators rely heavily on questionable tactics. For example, the 'Movies' application was discovered to be packaged alongside a VHD file spread on a deceptive website.
In general, adware applications are designed primarily to run advertising campaigns on the devices they are installed. The advertisements could take the form of pop-ups, banners, notifications, etc., and frequently disrupt the user's actions. Users also risk being shown advertisements for suspicious or misleading websites, adult pages, online betting/gambling platforms and more.
Having a PUP (Potentially Unwanted Program) active on your device also may result in additional risks. PUPs are infamous for being equipped with the ability to monitor, capture, and exfiltrate users' data. The captured information may include their browsing history, search history, IP addresses, device details and more.