Waxy maize starch as alternative to Maltodextrin/glucose for DIY carb drink mix?

For me, dextrose is usually easier to find and cheaper than maltodextrin.
Dextrose is also the simplest sugar you can find and will be faster to absorb than maltodextrin.
I don’t know why people use maltodextrin instead of dextrose. If somebody could explain to me I would appreciate.