I think it's fine.
I like the different greetings and they do not interfere in any way with safety when the RT around it is spoken well.
On an average day I hear "Namaste" "Salaam Alaikum" "Bonjour" "Konnichi wa" "Guten Tag" - as well as the appropriate "Goodbye", "Ma'salaama" and a casual "See ya".
There is room for both the ICAO-speak and the colloquialisms - as long as it is done safely.
The alternative is automatons. And we have enough of those out there already.