Translator degree student here. There is definitely room for machine/AI translation in the world, but definitely not where it should matter. If someone wants to read a tweet in a language they don't understand or get at least a vague idea of an article they can't read, machine translation does that for you. It won't give you a great translation, oftentimes not even a good one, but it can at least help you get an idea. It should not, however, be provided as a legitimate and complete replacement for proper human translation.
As for translating manga specifically, I do believe there's room for MTL even here, BUT ONLY provided that whoever's doing the MTL is proficient in at least the receiving language and puts the time and effort into editing the raw MTL. That way, even if the translation is not entirely correct, it can at least sound human and drop the completely blatant errors. Knowing at least a little bit of the original language too is very much desirable, because then you can first try to comprehend the original text, then get the MTL and then use both your first idea and the MTL result to then produce your own text. Because at the end of the day, that's what translating fiction should be: producing text, not simply swapping words and structures in a sterile way. That works when translation legalese but never fiction.
I've translated from languages I know before, and I have also made an "MTL" translation on this site once too. But there isn't actual MTL output in the published chapter. The final text is produced by me after trying to grasp the Japanese words and structures I'm familiar with, then reading the MTL output, then rephrasing the gibberish into something that actually makes sense, then showing it to a native English speaker to make sure it sounds natural (aka proofreading yk).
I very much believe that many of the manga I've read and loved here was made with the help of MTL, but the people working on it were competent enough to actually put in the work to put out a decent chapter. As it stands now, MTL cannot exist on its own. It still needs a human, preferably a proper translator, to edit and polish it.