Android display scaling has been a controversial topic in the Chromebook community since the removal of Android's DPI scaling setting in Chrome OS 67. The fonts and touch targets in Android apps appear tiny and illegible, making them incredibly frustrating to use compared to Chrome and native Chrome apps. There used to be workarounds to increase Android app scaling, but these methods don't work anymore. People have complained about it in the Chromebook community forums and have been filing bugs, and, to be honest, I can't blame them.
Back in February, some commits to the Chromium codebase revealed that Chrome OS would soon run Linux applications using a container. While it has been possible for years to run Linux applications on top of Chrome OS using crouton, it's a hacky solution that only works in Developer Mode. Google's solution would presumably work better, and perhaps not require Dev Mode to be enabled.
Even though Chrome OS is based on Linux (Gentoo Linux, to be exact), you can't run traditional desktop Linux applications. One solution to this problem is Crouton, a script that sets up a chroot of Ubuntu or Debian Linux on top of Chrome OS. While this does allow many people to use Chrome OS who otherwise couldn't, it's a hacky solution and requires enabling Developer Mode (which turns off most of Chrome OS' security features).