Most often, a hacker doesn't want access to your data so they can use it for anything in particular. They really only want access so they can stop YOU from accessing it. This loss of control on your part is what's most lucrative to them. If you want your access back, you need to pay up. It's as simple as that.
It's common knowledge that the best way to stay in control of your data is with strong password protection. Our post from earlier this year outlines the complexity you should factor in, but there's another layer of protection readily available to ensure hackers are as far removed from your data as they possibly can be: multi-factor authentication (MFA).