99.99% of keyboards have bumps on the ‘F’ and ‘J’. A good amount of people don’t know why.
The ‘F’ and ‘J’ keys have bumps so that you can feel them. If you know where these 2 keys are, you can find all the other letters by feel.
For “Touch typing” you put your left pointer finger over the ‘F’ and your right pointer finger over the ‘J’. However, this isn’t good enough for some people. The reasons why varies. Some people work with their hand and have developed callouses. Other times, the keyboard’s bumps are too tiny or may have been worn down. Other times, people use the number keys or the function keys and need “Bumps” on them to find them without looking down. Some people with low vision use them as well to help them type better.