And I was under the impression that losetup is deprecated and LUKS/cryptsetup is the preferred method now. I used to use a script similar to the OP with losetu

And I was under the impression that losetup is deprecated and LUKS/cryptsetup is the preferred method now. I used to use a script similar to the OP with losetup, but LUKS is better, at least from a UX standpoint, because you can multiple passphrases and it integrates with device mapper.