Comment by SllX
None of those are national security issues though, they’re QoL issues. The problem isn’t WhatsApp owning the market, it’s governments making the choice to only make their services available through WhatsApp and providing no alternative of their own to receive services. Every single “WhatsApp is too dominant” story I’ve seen usually boils down to governments acting as enablers for the supposed issue themselves.
You don't think WhatsApp for some reason stopping to work and airlines losing their default way to issue tickets is a national security issue? How about health care appointments with national ID and address on them being sent as PDFs and stored on Meta's servers? All of those are massive national security issues for me. It can grind the country to a halt for days on end.
There's a reason South Korea has laws requiring all data on its citizens and geography to be stored in Korea. Even Google Maps doesn't quite work in Korea.