For comfort!
After one-click activation of mediathek it populates all my past queries and I can browse through it. The screenshot at
https://addons.videolan.org/p/1241457/ shows a playlist set up prior to activation through the search field (not hardcoded).
There are also minor reasons for caching as the database in use is availalable as .xz for download, decompressed size > 100 MB, size of Lua table'd be > 300 MB.
But, of course caching could be done elsewhere (e.g. os.getenv"TMPDIR" or os.getenv"TEMP" or os.getenv"TMP" or "/tmp".)
Disclaimer: This is not a request for having vlc.config available for sd scripts.
Thanks for reading.