Though obviously it's not the reason it was adopted, it is kind of neat that using a dead language for scientific terms disambiguates them cleanly for the purposes of searching.

Any live language would have accidental matches (even quoted) where it's just the obvious thing to say, a la "born without a cerebellum".

having dead languages to imprecisely map to a word (but nobody knows that because no one really speaks the dead language) isn't any better. It also creates barriers and wasted time in learning the practice. The average individual has to deal with that folly even more when it comes to law.