Surprisingly large number of businesses run on whatsapp, as a consultant in Asia it's prob around half the businesses I've worked with prefer it over teams/slack. If Meta had been sensible about API access Telegram wouldn't have even got a foothold.
south america and africa are both heavily invested in whatsapp in the business space.
WhatsApp is actually more popular than Slack, isn’t it? In my country, almost everyone uses Slack, and I’ve hardly ever heard of any companies using WhatsApp, so that was surprising to me.