Apple has a problem with discoverability in quite a lot of features. There's many small little things in iOS that users don't know about and likely will never find out about, perhaps because they want to keep the UI clean.
There’s a whole Apple app - Tips - included with every iOS device, dedicated specifically to these small features.
It’s updated by Apple with new tips and tricks regularly, and you can choose to be notified each time a new ‘episode’ is released.
I imagine most iPhone users don’t know it is there!
On the one hand, thanks for the tip! On the other hand, Apple has an enormous discoverability problem, it's getting worse, and they're responding by making the UX dumber instead of addressing it head on.