Desktop Stuff -is This Suspicious

I scanned a batch of papers as pdf's. Used the Brothers utilities suite. I wanted them to go to folderr on my desktop. They did not. they went here. C/Docu,ents and Setting/*****/dropbox. and put them in a folder there.
What is dropbox? I never heard of it. There's some important stuff in those pdfs, should I be concerned?

 

Dropbox is cloud storage - like iCloud, OneDrive or MediaFire - Do you have a Dropbox account? If yes then the scanner may be set up to save scans to the Dropbox folder automatically where they’ll be automatically synced with the online version.

 

Remember this?

https://forums.majorgeeks.com/threads/get-rid-of-dropbox-forever.322301/

 

Doh! I do now .I thought I uninstalled it, so why did my pdfs go there. Now I cant remember the email I used, passwords, etc.

 

What I want to know is:
If drop box is uninstalled, why does this dropbox folder exist on my computer?
If it uninstalled why does the brother scan utility put a copy pdf in that folder