A digression, but I don't think this is actually the case.
I readily acknowledge that literally is often used when a sentence is figurative; that's not the same thing. For literally to be used to mean figuratively the utterer would be worried that, but for the presence of "literally", the sentence might be understood to be literal.
I contend that the role "literally" usually plays is that of an intensifier. I believe it plays that role through ordinary application of hyperbole: the utterance "X is literally Y" is usually meant as "X is very Y; X is so Y it is almost as if it were literally Y; but of course you understand that it was not, in fact, literally Y - we're all reasonable people here."
In much the same way, when someone says "You left me waiting for days" and it's been a handful of minutes, we don't say "'days' sometimes means 'minutes'" - we say that people exaggerate.
I recognize that I'm disagreeing with at least one dictionary; I believe they got it wrong.
And I won't claim that there is literally no single person who in fact uses "literally" to mean "figuratively" - but I have never encountered such an example and I believe it to be rare enough that we can consider it an error, even in a descriptivist treatment.
I think that’s because when science started to get serious, Latin happened to be the lingua-Franca of those in Europe who could afford to be part of it. Equivalent deal for why we use Arabic numbers.
I wouldn’t be surprised if I turn out to be wrong, but I was taught the causal chain was:
1. The Romans spoke Latin
2. Catholic church based in Rome, did everything in Latin
3. Between tithes and indulgences, church got rich and powerful
4. The rich and powerful keep learning Latin to keep up to date with news from the other rich and powerful
latin was used because it was the language you used to write important stuff, it was with the creation of france and Germany that other language were upgraded in social status