"When I launch SmarTeam – Web Editor, a Workflow license is also taken. Is it possible to disable the Workflow product for users who do not utilize Workflow?"
To disable the Workflow functionality for the users who do not use Workflow, you can create an override in the System Configuration Editor Tool that restricts this functionality for all users or for specified users.
To enable Workflow for a few users, it may be easier to create a Domain override, set it to FALSE, then set a User override for each user that needs to use Workflow. But what this does not identify is, if the user enables the workflow inbox display again by selecting the little up arrow at the bottom of the web editor screen.
Then they log out, they effectively reactivate taking the workflow license each time they start the SmarTeam web editor, as it remembers this maximised setting. This highlights the importance of training users to minimise the display of the inbox before logging out. Or possibly a better way would be to access their SmartBox via the button on the task bar of the web editor.