Both Dropbox and cloud services are in place for very different purposes.
To make the distinction clearer it is best to describe Dropbox and similarly the Google Drive facility, as more of a sync and backup application. These kinds of online services are excellent for making selected files available to someone else’s personal computer or mobile device and to allow synchronisation between all those devices. So if you make a change on your files in Dropbox via your office PC, you will still get the updated and latest information added to your iPad for example.
But Cloud based services offer different facilities. The central point is that Cloud based back up services have different function in that they are in place when there is a disaster situation. If your computers, iPads or any other device is stolen, damaged or just has a problem, you can sit at any device and retrieve all your information which will have been stored as data.
It’s obvious that there is an overlap in the functions of both these services and it can be argued that both allow the upload of files to another location , which effectively is protecting that data in both instances. They also serve the similar purpose of making files accessible from anywhere, anytime on any device as long as the internet is available and you are in possession of your private password and login details.
The major differentiation comes down to what they upload and to where.
Synchronising applications require the user to put all their files in a single folder set up specifically for that function. In order to ensure these are backed up all the library files and even some parts of your AppData might need to be moved into the Dropbox and Google Drive type services… and many of these have limited space available. ON the other hand Cloud back up will give you the ability to take any folders from anywhere in your drive or from many drives and the system in place is usually one which allows all library folders, the desk top and any other vital information you deem invaluable to be protected by default.
The back ups cannot be used for synchronising with others in a work or office situation, but the others in the office can separately also back up their information online to this secure area as well. This also does not allow you to alter the files you have backed up as these will not reflect in the cloud. In this case, a fresh back up of the new information will be required. Some of these cloud back up services do offer synchronization to their clients but this will require software, which will probably not run from the backed up information.