Because the English version could say anything and be massively divorced from the original script. If the original Japanese text says 50mph and the English version says 5000000mph, the Japanese one is the one that should be taken. If you take the English one, you aren't taking what the original...
forums.spacebattles.com

I wonder if they will ever take this advice for:
OPM
MHA
Kimetsu No Yaiba
They won't because we know the reason why but holy shit, I hate that they actually use this as a defense to disprove feats now despite not realizing that some translators actually have direct access to the company/director/creator or the company itself will force in certain translations on their own terms.