IIRC, you have an option to save images to the cloud using CC.
(I dunno personally, as I don't use it)

Many net providers now charge for uploads as well as downloads.
Some do, some don't .. you need to check with yours.

I can't imagine many of the net connections CC does such as validations and suchlike will use all that much data allowance.
But if there's some new cool super tool added, it will probably mean a major upgrade ... and therefore a lot more data.