When we work with our clients we frequently see them backspacing over individual letters or characters one at a time to erase a word, phrase, or url in the browser address bar. Stop doing that!
When text is selected (indicated by the blue highlight) just start typing what you want in its place or hit the backspace or delete key to delete it altogether. There is just no need to backspace over each individual character.
Yes, it works like that on your iPhone and iPad as well.
Bonus Tip: Double-click to select a word, triple-click to select a paragraph, and CTRL+A selects a document.