The ability to boot from an external drive on an Apple Silicon Mac may not be an option for much longer, with the creation and use of the drives apparently being phased out by Apple, according to developers of backup tools.
For some users, the ability to create a bootable drive for their Mac gives them a safety net, in case the main drive on the Mac breaks or encounters a problem. It is a backup technique that can get users back up and running very quickly, but the option may not be available for much longer with Apple's transition to Apple Silicon.