"The term "full-disk/on-disk encryption" is often used to signify that everything on a disk is encrypted, including the programs that can encrypt bootable operating system partitions."

Are you going to tell Markus Gattol he's wrong? No? Good, let's move on.

What matters here is the security, and the adoption rate of TrueCrypt is/was through the roof, because of how it allowed folks to move encrypted volumes across various platforms without much hassle.

What you wrote seems to intimate there's no actual need or value in moving encrypted volumes across platforms, and that if folks actually want to do that they should just encrypt individually and at a FS level and do so using PGP, which has existed for years, and whose adoption rate and ease-of-use are both, compared to TrueCrypt, through the floor.

The fact is, people want to move encrypted volumes across platforms. It's not more secure than anything else, but it presents a workflow that might actually be more secure, due simply to it's ease of implementation.

You're right, security is all that matters here, and folks aren't going to be secure if it remains impossibly difficult to be secure.