Yes windows pe is also used by utilities as macrium reflect for standalone boot in case of system image restore .
Today i use an usb key wich contains a 32 bit windows pe image and a truecrypt container
so after booting in compatibility mode (not uefi) i can start macrium and open true crypt container
and restore system image.
my whishe is to use 64 bit image ,bootable in uefi mode, and can open truecrypt /ciphershed container in 64 bit