Many clients aren’t familiar with WordPress and have never used a CMS before, so handing it off to them with unlimited access to the backend is like giving them a live grenade. Things are gonna get messy. They may mess up your design, or worse, break the entire site. Then it is left to you to pick up the pieces. That’s why it is best to get ahead of this possible disaster and take the time to set your client up with the right user role settings. This ensures they can access only the parts of the site they need and nothing more.
Sent from my Samsung Galaxy smartphone.