And yeah, i have downloaded Wikipedia (in ZIM format) :-P
It isn't really for some doomsday preparation reason, it is just that sometimes the internet doesn't work (it doesn't happen often but it does happen) or i do not have internet access for whatever reason or stuff simply disappears/changes.
In fact just yesterday night i wanted to lookup how something is done in Bash and after trying to search for it, i noticed my Internet wasn't working (it took ~1h to resume, it was quite late in the night). So i just started a local LLM and asked that instead :-P (i do have the info manuals for bash - and other stuff - installed but they are a PITA to search if you don't know exactly what you're looking for).
One thing that annoys me though is that it is basically impossible to have an offline copy of a modern Linux distro. Sometime during the late 2000s i bought the full set of Debian DVDs, but Debian stopped providing ISOs years ago. Of course with how big distros are nowadays you'd probably need something like 100 DVDs :-P. At least there is Slackware.