Others have replied with the reasons, i.e. data vs SMS price. I would just like to comment on:
however no one on my continent uses it. Why is it so popular in the EU and other parts of the world?
No one in your country uses it, people definitely use it on your continent. Latin America is almost 100% WhatsApp, SMS are seen as obsolete there, even if you meant North America Mexico uses WhatsApp. I think the only countries in the world that use SMS are the US and Canada, which coincidentally are the only countries I've visited where I had to worry about running out of data on my phone.
The code is there, yes, but it's skipped entirely, so the binary size stays the same, but it's faster because it skips parts. The big brain on the person that wrote that must also tell him that skipping a scene on a movie means the movie takes the same time because it's the entirety of the movie plus the skipping of the scene.