This is a matter of taste.
> I have never had a conversation in any dead language.
This is also a matter of taste.
> Prose literature is actually a more recent development, so if you want to read ancient stories in the original, which are awesome, you will be reading poetry.
This is more of a matter of which language you're studying.
> because of meter [poetic language] is memorizable
This is bizarre. Your claim is quite correct as to speakers of the original language, but we've stipulated that the language is dead. In general, students cannot identify or even notice poetic meter in the dead languages they study. I really enjoyed scanning Latin verse, but that is because I enjoy math. To more "normal" students, scansion is infamous for being painful and difficult.
I responded to the perceived suggestion that studying poetry is an effective method of learning a language. I don't agree with that: poetry is more difficult to read than prose, and the lessons you may draw from it are often specific to the genre, not the language. For example, if you want to read Latin poetry, you will want a working knowledge of Greek grammar, which is sometimes used in preference to Latin grammar. The Roman poets could count on their audience to know Greek. But learning Greek grammar is not actually a particularly valuable step in studying Latin grammar.
You don't read poetry in order to learn a language. You learn the language in order to read the poetry.