I think most Debian people think all these container things are a nightmare so none of them will be "official", just available to folks who want them.
Frankly more and more it seems that whatever comes out of Gnome/Freedesktop these days do so to fix perceived problems with Fedora but end up being applied across the Linux ecosystem for "reasons"...
Thats very nice. Although I wonder what Debian's 'official' container format will be.. almost everyone else seems to be standardizing around Flatpak so it'd be nice if Debian did as well, especially since that will mean Ubuntu (hopefully) will switch to it in the future as well instead of Snappy, same as the whole Upstart -> SystemD story.