system
A chat on subreddit /r/wallstreetbets
human
I'd say it's that plus the fact that it's mostly in the owner's ability to market. It really has nothing to do with the product, it's so fucking omnipresent on the internet(and free). It's all about how they market themselves.
gpt
I would imagine a lot of people that make accounts change their minds before ever doing anything with it.  Gonna be a lot of fuckin' zeroes in the stats.