Using 'dw' deletes from the cursor until the end of the word.
Using 'daw' deletes the whole word "around" the cursor (hence 'a' command) - meaning you don't have to pay attention to the cursor position, it could be on the start/middle/end of the word and the result would be the same.
No worries. There's always more to learn. `dw` is a motion command as in "delete to the end of the word. `daw` is a text object command as in "delete a word." There is also a difference between `daw` and `diw`, which is delete inner word, and `daW` which is delete a WORD.
Using 'daw' deletes the whole word "around" the cursor (hence 'a' command) - meaning you don't have to pay attention to the cursor position, it could be on the start/middle/end of the word and the result would be the same.