iOS what is "slide to type" option in keyboard prefs?

See: Type and edit text on iPhone - Apple Support

including the following:

Enter text using the onscreen keyboard

In any app that allows text editing, open the onscreen keyboard by tapping a text field. Tap individual keys to type, or use QuickPath (not available for all languages) to type a word by sliding from one letter to the next without lifting your finger. To end the word, lift your finger. You can use either method as you type, and even switch in the middle of a sentence. (If you tap after sliding to type a word, it deletes the whole word.)