Personally, given all of the cloud storage options, I think it would be better to allow people set up a number of storage options, then they could work directly with Zapier.
Just a thought.
Provided you have the space on your local PC you can do what I do - keep a Dropbox folder locally which is synced with a Dropbox cloud folder. Since the DropBox folder on your computer is like any other local folder there is no compatibility problem with most software including MM - you save a file to the local folder and Dropbox automatically syncs it to the cloud.
It's sensible to have a synced local folder anyway as in effect it backs up the cloud folder - and vice versa. You never know when you might not be able to access the cloud folder.