>In the UAE, where VoIP is illegal, the government was not able to selectively block voice traffic since it is indistinguishable from text traffic. So they had to ask WhatsApp to block voice functionality whenever a user is in the UAE.

Authorities can selectively block WhatsApp voice calls, it's been done in Oman where I used to live. If I leave Oman and use WhatsApp in an uncensored country, voice calls work just fine.

This is not the case where WhatsApp is registered via a UAE number; the blocks persist no matter where you connect from.