Bootable backups have been deprecated for several years
Well, it's almost 2 years later and we are pleasantly surprised to see that Apple has kept bootable copies afloat. CCC has continued to be able to create bootable copies of macOS, and we'll continue to support that functionality as long as macOS supports it.
With all that said, Apple hasn't revised its stance that this capability could be dropped or broken in any future update. So, if you have an Apple Silicon Mac, we recommend that you treat bootable backups as a redundancy strategy. Take advantage of it while it's around, but don't put all your your eggs in that basket.
While some developers seem surprised by a change in macOS 15.2, we've known for several years that making bootable backups would eventually become impossible. We shifted CCC's strategy away from relying on External Boot so our users wouldn't be affected by this inevitable result.
I took a few days off last week to help a family member, and returned to find the Mac community all aflutter with comments about bootable backups not working after the 15.2 update and comparisons of Apple...