Very simple - convenience.

Most people want to check how much power their PV produces from their phone. Yes, a proper solution like a openDTU that stays local only would be better - but it requires setup which most people simply lack.

Well, the correct german word is to say ‘Fachkräftemangel’ which in my experience translates to ‘We need someone with 20+ years of experience, that we can pay like an intern’