My guess is it’s meant to come off as more authentic and conversational, like an informal chat.

It's often used as a tone signifier: https://www.theguardian.com/society/2025/feb/18/death-of-cap...

Yeah, I suspect that's the intention. There's a definitely a cultural break. To me, lowercase creates a casual tone in texts/chat. But in long form, especially published (i.e. purposefully displayed to an audience), it sends me a tone of disinterest or laziness at worst; or at best, simple innocent ignorance/mistakenness (like misspelling). Clearly neither is the case here though.