More catches. It's marketed that Chromebooks can install Android apps, but it's not true across the board.
Older Chromebooks made before 2015, new "school-grade" ones with cheaper parts meant to be budget-friendly but tougher built, and certain processors (not as clear cut as Intel vs. ARM, but procs with no Virtualization Support) can't touch Android Apps. The same models are also out of luck concerning Linux Apps. (They can still install a Linux chroot file system and either run it parallel to Chrome OS or dual boot into it, but it's in Dev Mode and has that annoying beep and 10 second wait each time.)
Fragmentation is just as present in ChromeOS as it is in Android itself.