Let me say that again:
The goal of keyboarding is students type well enough that it doesn’t disrupt their thinking.
Much like breathing takes no thought and playing a piano is automatic, students must be able to think while they type, fingers automatically moving to the keys that record their thoughts. Searching for key placement shouldn’t interfere with how they develop a sentence. Sure, it does when students are just starting, but by third grade students should be comfortable enough with key placement to be working on speed.
To type as fast at the speed of thought isn’t as difficult as it sounds. For students in school, ‘speed of thought’ refers to how fast they develop ideas that will be recorded. 20 wpm means they know most key placements by touch. 30 wpm is the low end of not interfering with thinking. 45 wpm is good.