Source Tree - What is source tree for?

I already try using this?

One question that I am still doubting. Is it safe? ( I am still new user)

Thanks in advance.

We use sourcetree at my work and it's a pretty good tool. It's just a repo interface of course when you get right down to it but works well and has some nice features.
I now use it with bitbucket for my personal projects as well.
I can't comment on how safe it is compared to other alternatives.

Like other user cannot see my other files unless I am giving them permission.