You need to make the decisions, keep track, and do the work. If you've got the tools made for you, excellent. Otherwise you also have to build and maintain the tools -- which is my point.
There are no more decisions to make one way or the other. If you're keeping a VM image updated with new packages, that's either a) automated with something like unattended-upgrades, or b) a manual scan of DSA's with decisions as to whether they're important enough to apply and to which boxes they need to be applied. It you're rebuilding a container image, that's either a) a 2am cron job to do a blind rebuild that captures the latest package versions anyway, or b) a manual scan of DSA's with decisions etc etc...
The 2am cron job, if you go that way, is, assuming you've got an automated build anyway, a one-line bit of config somewhere. It's not something I'd usually think the words "build and maintain" would apply to.
