I mostly text on Signal with disappearing messages so I wouldn't be able to do this. Most people are fine with disappearing messages at 4 weeks, but a few people like to keep their chats forever.
I wanted to do this so bad back in like 2009. I archived MSN messenger chats and my texts and everything and I figured sometime in the future I'd be able to analyze them and maybe even train a chat bot to imitate me. But over the years I lost hard drives and cell phones and accidentally deleted stuff and yeah it didn't happen. Very cool this guy was able to do it