Mobile keyboards are tricky. You can simulate mobile keyboard clicks using automation frameworks, but depending on how you do it, you can simulate these clicks even when the keyboard isn’t visible, or when particular keys aren’t visible. Here’s one example:
As participants in this thread that’s been going on for seven years and 800,000 views can attest, Android keyboards are famously hard to manage. Not only are the API’s finicky, but different versions of Android and different sized phones may work differently. If you’re developing and testing on one or two simulators, you may be missing problems that your customers see right away. In this example, the user can’t click the “Register” button even when a test script might be able to.