Problem to solve:
Someone starts a account for their business, buys a template, fill it with their content and are happy. Then they want to extend the site but don't have the skills to do that. They need help.
They could just give someone access to their whole account but it could be projects in there they don't want anyone to see and they also don't want change password every time they want to restrict access.
When sharing a read-only-link you get a option to share it with another webflow user, maybe someone with a pro account. With that link that person can make changes to the actual site.
Another way is to make some sort of a mini team account. The client who want help can give someone access to the site/project who then can access it in the dashboard.