Add man pages and docs
Unless you have packages that are ’expensive’ either in terms of the memory they use while operating or in terms of the amount space they take up (since in Alpine ‘data’ (and in ‘diskless’) mode packages are stored in RAM while the system is booted) you should have plenty of available RAM and storage to add the online documentation (mostly in the form of man pages).
Online documentation is optional but it makes life a heck of a lot easier, especially if one is at a physical console of a CLI-only system and thus searching web pages for answers is therefore impractical.