"data is being used for which purposes". So if they find you are doing something they do not like, they report you.

I hope that people worry not only about Dropbox. Fakebook is a data mining company. What is Google? Microsoft? All of the AI companies?

What is your car sending to the maker? Do you know what your "smartphone" does behing your back?

The sentence you posted doesn't say that they changed their behavior, just that they explained it better. Presumably they also gave you a copy of the new policy? Do a diff between old and new and see what changed. There are your details.

As their entire business model is built around you giving them your data, it is actually a good thing that they have a policy about your data. But you gotta read that policy to know whether its content is good or bad.

I have no idea whether or not their policies should cause concern, but if they are concerning, it isn't because of that line.