but most phone numbers you are clicking on a web page (the cited use case) won't have a whatsapp account behind it
1. Long press on the phone number, but don't tap it otherwise it calls
2. Choose Copy phone number
3. Create a contact
4. Refresh WhatsApp by quitting and reopening
5. Find the contact on WhatsApp and call
If you're calling multiple companies for bookings or quotes, repeat this over and over.
This said, it's good to see that apple is slowly adding things so basic that it's baffling they are not there since years.
Could imagine that countries like India the majority of buisneses also have an whatsapp account.
Never tried it, but it seems that calling a regular non-account via whatsapp will still work. But routed through watsapp servers. If someone can confirm or deny that, would be cool.
so don't downvote me if you're in india and certain countries in sa asia where that is the case but that's not the whole world outside the us