They probably don't; I doubt many designers are thinking "wow, I really want to inundate my user with pop-ups," it's more that analysts have likely got numbers

They probably don't; I doubt many designers are thinking "wow, I really want to inundate my user with pop-ups," it's more that analysts have likely got numbers showing that having x calls to action yields y% more subscribers or can produce z% more ad revenue. I can't stand chatbot popups on websites, because I know what I'm doing and don't like being bothered, but I can imagine that an older or less tech-savvy demographic might find the instant tech support quite novel.