Thanks for the good explanations to @nicole.faerber and @MrChromebox !
P.D. The quote I cut, because I do not have a say in the work to be done on pureboot to realize protection by heads for the EC. I just believe that it true that it’s not easy to implement.
Maybe I overreacted a bit on the word “slow” as I would have also done for “inconvenient” or “complicated” in the context of security ;-). Sorry if I did!