This is the pragmatic approach to the issue. Switching from a ubiquitous communications platform to something that practically nobody uses (relative to WhatsApp's active user numbers) carries a high cost in Weirdness Points[0], and those are only very slowly renewable unless you want to be seen as "the rebel of the family".
[0] https://www.lesswrong.com/posts/wkuDgmpxwbu2M2k3w/you-have-a...