I've only read pages #1 and #9 of the thread, but I'm still none the wiser as to how or why this is a problem. Other than aesthetics (which can't be it, Shirley?) and the lack of read-receipts, I really don't get it.
Overall there are bigger things to worry about for me, but as ever YMMV.
- Across my wife's family we have a multi-generational UK chat group on WhatsApp, I don't know why it ended up there, perhaps before iPhone group messaging or because brother-in-law has a Pixel whilst the other seven users are iPhones. In the furore following Facebook buying WhatsApp I suggested moving to Signal, but no-one else cared a jot.
- My wife does all her texting using WhatsApp on iPhone - I'm the only person she messages regularly using iMessage.
- I don't much care for Facebook Messenger, but I have two friends who default to it, so I have to keep it on my iPhone or I'd not see their messages at all.
- My kid is 19 & not one of their UK peer group uses WhatsApp or even has it on their phones, go figure. They use Snap or - bizarrely to me - message each other via Instagram
Overall there are bigger things to worry about for me, but as ever YMMV.