Sure, I was creating chroot's manually with a bunch of bash scripts and rsyncing around filesystems like nobody's business... but it wasn't something you could

Sure, I was creating chroot's manually with a bunch of bash scripts and rsyncing around filesystems like nobody's business... but it wasn't something you could replicate across organizations and even environments. It was all hand picked and meticulously developed. Docker (and the many, nice alternatives) standardize the format and build nice features on top. It abstracts away the lower-level stuff. Neat to know about if you're interested in how it all works... doesn't mean it's harmful.