luceos Yeah that's right, but there's two different things to achieve there.
You don't want to run a command to update plugins and suddenly find unwanted behaviour because a new Flarum version has just been released which you haven't seen and haven't had time to check compatibility with your system, plus you need to take a full backup of your forum including the database before upgrading core.
luceos As we suggest everyone to upgrade as soon as possible to the latest Flarum versions, my command would suit that need.
While that's ideal indeed, most people won't do this. Remind me again how out of date is the blue forum?! vB 4.2.2 Patch Level 4 released in 2015 and incompatible with PHP version 5.5 or later. People are sometimes determined to run obsolete stuff for as long as possible, forum software is not immune to that. I reckon most people will take at least a couple of months to update core, and many will take a LOT longer than that, some will just continue running the version they first installed forever unless something breaks.
At some point you should probably think about putting a persistent nag notice in the forum admin area for when the major version is out of date by more than a month or two.