Whatsapp is more popular in Malaysia (not rest of the world) but Whatsapp is kinda plain if compared to other messaging app like Telegram…

iMessage integrated with all Apple services so is more convenient to share stuffs if your group of friends are all iOS users which in US most people using iPhones …

Some apps are integrated to iMessage for sharing. It is neater and do not need to do it from the 3rd party app, for example i can share OneDrive file direct from iMessage or song from Apple Music or location from Google Maps … so if you are chatting with friend on iMessage and wanna share a music, you do not need to open Apple Music and copy link of the song and go back share it on the chat app …

In most cases, if we want to share certain link and stuffs using the respective app and select which chat app we wanna share it to and to which group/person, redirect to the chat app to share… it is never the other way around

This feature requires the app developer to support iMessage access not widely use so most of the app that supports are Apple company app … like Apple Music, Apple Cash, etc

Whatsapp only the regular photo video file location contact …