The Latin language was the vulgar language of Rome, used by scholar, orator, prostitute and the apocalyptic beast. The Roman Church wanted to use the common, vulgar language, making this the sacred language of the Church, that is, the language into which Scripture would be translated (the Vulgate [from vulgar or common]), and in which the Liturgy would be celebrated, including sacramentals like exorcism.
Some decades before the dumbed-down non-translation of the first ICEL attempt to translate the Mass into English some 40 years ago, translations of the rite of exorcism started to appear. They were clearly translated by someone who either did not know Latin very well, or who just wasn’t worried about how precise he was, perhaps because the “translation” was never meant to be used. It was just an indication of what was happening in the Latin text, which surely would be used.
Texts are important inasmuch as they are used to communicate. Different texts communicate differently. One would want to express that which the Church wants to be expressed, especially with something so sensitive as exorcism, no? This would be the primary benefit of using Latin.
The language itself as a language has nothing to offer more than that. “Is using Latin more powerful in exorcisms?” is a question that is raised frequently enough. Very frequently, in fact. No, it’s not more powerful. One shouldn’t use it superstitiously. And, by the way, I don’t care who you are or what schooling you’ve had, the devil is better at Latin than you are. If you use it out of pride, he will make your head spin. Humility in all things.
Even if an excellent translation of the 1614 ritual were to be used, it is not always a good idea to use it, depending on the circumstances of those present. Not all those assisting might have a stomach strong enough to take even hours of these kinds of texts in English being recited, so dramatically evocative are they.
There are parts of the ritual for which you might want to use a translation, even if you laudably recite the rest in Latin. For instance, the litany of saints.
However, for obvious reasons, it would be good to ask the mandated questions to Satan in Latin or in an obscure language you are certain that the possessed person does not understand, and has probably never seen on TV or heard on the radio.