A large part was to preserve cultural knowledge, which is kind of like answering questions about it. What wisdom or knowledge does this entail. People do the same with religious texts today

The other part I imagine was largely entertainment, social and memory is a good skill to build.

It doesn’t seem that different from having to write a book report or something like that. Back in school, we also needed to memorize poems and songs to recite them - I quite hated it because my memory was never exactly great. Same as having to remember the vocabulary in a foreign language when learning it, though that might arguably be a bit more directly useful.