Using broolz::sync allows you to share your files with those you trust, helping you keep your folders up to date.Do you use two computers?
Perhaps you have your own PC and your partner does too. Seems reasonable to want to share family photos between your computers - though maybe you have some of your last walking trip that your partner isn't interested in. How do you ensure your partner gets the photos they want, and not the photos they don't? What if you add some photos to your computer - how will your partner get copies then?
What if your use a PC at home and a laptop you use on the go. Isn't it annoying when you make some changes at home and then find you don't have those changes on your laptop? It can be worse still if you make changes to a document on your laptop and then changes to the same document on your home PC. Which set of changes do you lose? How do you back up this entangled mess anyway? Do you make a backup of your PC data and your laptop data, and hope they don't diverge too much?
Help is at hand. Using broolz::sync, you can simply specify the folders you want to share and who to share with, and know they will be automatically shared, in real time, whenever changes are made.