Why an extension
On ChromeOS, the browser is the platform
A Chromebook runs Chrome, Android apps and, on some models, a Linux container. It doesn't run Mac or Windows software, so every desktop recorder with Screen Studio-style effects is off the table. Extensions are the native way to add features, and they install in seconds without admin rights on a personal Chromebook.
Screenix for Chrome records the tab you're on through Chrome's screencast, without the system cursor, and keeps mouse movement and clicks as data. It then draws a smooth cursor, zooms on your clicks and frames the recording on a background. Instant mode hands you the MP4 the moment you stop. Studio mode opens an editor for trims, zooms, cursor themes and the camera bubble, then exports up to 4K.