I mean probably not, at least not for a while. Perhaps some charmingly straightforward people have precisely the same persona online and off, no matter the situation, but I suspect most do some amount of code switching. An LLM would be best served in its goal by approximating the persona, which wouldn't translate well. I could be wrong (maybe we "leak" enough that a convincing rendition of the persona would necessarily take into account some amount of interior state) but it seems to me that personality is a convenience adopted for communication.