You have a valid question. 😊
But u see, there are so many different translations of Mahabharat, in which, many things actually contradict each other.
Now, if people start considering all translations, and start arguing giving contradictory citations from various translations, then this forum will become chaotic.
Hence, to keep the confusion at a minimum level, one translation has been set as the standard.
Besides, KMG is available online for free, so anyone can access it.
And English is what we communicate with here, usually. And not everyone understands every regional language.
So, an English translation will help.
I know, your question is justified, and KMG is not the ultimate Mahabharat, but sticking to it alone, makes it easier. 😊