sailor's goal is definitely not to bring security, we all perfectly know chroot is not the way of isolating a host filesystem from attackers. Instead, sailor provides a convenient way of testing environments without compromising your workstation / dev station filesystem.
Which was, as it happens, the reason chroot was invented (to test the installer of newer versions of UNIX without having a brand-new physical system). Better tooling around chroot is absolutely useful.
I guess it's a misnomer to use the word "container", since that usually means things like Linux containers with security isolation almost as good as OS virtualization.
Right, the "container" word is now vastly associated to docker, yet I picked a word I know IT people will get and which is generic enough. I'll think on an alternative buzzword ;)
Thanks for your support!
Duly noted, I just added a word about it on the GitHub page, and you're right, I should run the examples services with a dedicated user as I already do for the nginx process.
Thanks for your feedback!