As each workspace has its own subscription and billed separately you can have a number of workspaces where you can be either a free or a pro user. This helps in cases when you have multiple teams working in parallel for different customers or with different projects.
For example, say you have 2 huge projects for 2 different customers going in parallel. Team A works on a short term project (3 months long) and your customer is paying for your UXPressia account for this team. In this case you can add your customer as a billing manager in the Team A workspace so the customer is not included as a collaborator and handles billing only. Once the project is complete, you can cancel the subscription for the whole workspace.
At the same time, Team B is working on a longer project which has already been running for a year and you don’t expect it to end any time soon. This subscription can be paid by your company and you don’t want it to end when Team A finishes their work. In this case, you can have another workspace on an annual subscription with other billing manager and payment terms.
Team A and Team B will have no information about one another. They can benefit from Sharing with the workspace feature without jeopardizing privacy of the project as their visibility will be restricted to the team members within a given workspace.