It’s because the developers are self absorbed narcissists who think you’re staring at the prediction bar while typing and so if you are still typing after it shows you that word, even one character, that must not be the one you’re trying to type. What if you’re using a keyboard how it’s supposed to be used, as a utility to interact with something else, and so looking at what you’re typing as you’re typing it, like a normal person? Guess they didn’t think of that.