I understand the risks of password reuse when we share the password with 3rd parties as perfectly discussed under this question: Is password reuse a problem if the password is very strong?
However I wonder if there are risks associated with reusing a strong password for disk encryption like FileVault, BitLocker, or dm-crypt? And reusing the password only for external disks, not anywhere else.
Except for the risk of having multiple disks exposed by a successful brute-force attack on one of them, are there any other dangers?
I see a risk if the same password was used for a system (boot) disk and an external one. In this case a keylogger running as a process under the OS could steal a password typed when an external disk is attached, thus exposing the password for the system disk. However if the same password was reused only for external disks?