I'm trying to show that using a method that can only produce nonsense out of a given source is not the best way to demonstrate/prove _anything_ about the source. At best, it proves that literal translation is garbage, which is something everyone knows (except at tech giants, apparently).
There is only one way to translate "quatre-vingt-dix-sept" in English while preserving its meaning: "ninety-seven".
Pointing out the decimal <-> vigesimal switch (and the historical debates around it, for example) or the fact that the two systems cohabit would be far more useful and interesting than constructing a strawman in order to conclude that a language is "insane".
If you perform the same literal translation to 57, it doesn't look "insane". When you say the method "can only produce nonsense", I think you're just flat-out wrong.
A similar literal translation from english to english of 97 would be nine-tens-seven. English has some irregularities in the teens but it's decimal all the way through. French switches from decimal to vigesimal.