DME is used alone without other sugar, and, honestly, it doesn't make any difference. Some people are purists and think that a little sugar will harm their beer. It just aint so. In my experience, corn sugar is a much faster, cleaner priming sugar and contributes zero taste to the beer in the quantities used for priming. DME will definitely take longer to condition and you use a bit more of it usually. So, no real difference except corn sugar works better for the purpose.
Oh don't give me none more of that Old Janx Spirit
No, don't you give me none more of that Old Janx Spirit
For my head will fly, my tongue will lie, my eyes will fry and I may die
Won't you pour me one more of that sinful Old Janx Spirit