I found this when I was researching "OMG!#! systemd even includes QR code library." Why would they do that? They are smart guys after all, they don't do things without purpose. Then I found this gem. It is actually used to ensure the system is intact and no one has tampered with logs, etc:
It's called Forward Secure Sealing: http://lwn.net/Articles/512895...
Another small gem is "Why, oh why, they created NTP clone?" There is a very good rationale for that, like having coherent timestamps on embedded device boot:
Naturally these are optional, and not forced upon you.