In many regions, using WhatsApp is not really a choice.
Individuals might be willing to contact you via other channels, but group chats won't move to another platform unless you are dealing with people who actually care about their privacy.
I don't use WhatsApp (can't use it due to not having an approved smartphone, and not wishing to accept Facebook's terms of use), and I miss things. Not a lot, and nothing critical, but my partner and I do miss out on some social things.
So you decide for the former.
By not supporting WhatsApp, it forces the user to solve the problem that he/she makes a very bad decision with respect to his/her privacy.
Hence my question in response to gregknicholson's statement:
>> This is one of the problems the Librem 5 is designed to solve.
> How?
It makes it easier for those who _want_ to switch, but don't have the confidence/skill/energy to figure everything out on their own.
Similarly, Disroot made it easy to switch away from Google, by providing a complete (for my purposes) drop-in replacement; Ubuntu made it easy to switch from Windows.