They indeed just "license" the games to us:

The Services and Content are licensed to you, not sold. This means we grant you a personal, limited, non-transferable and revocable right and license to use the Services and access the Content, for your entertainment, non-commercial use, subject to your compliance with these Terms.

For termination, it's not any reason but a lot of reasons, including the here discussed:

for any other reason in relation to your actions in or outside of the Services; upon notification, where your Account has been inactive for more than six months.

The first one opens a lot of options for them to find a reason. None of those would trigger any reimbursement, though.

Consequences of the Termination/Suspension of an Account.

You cannot use the Services and Content anymore.
In the event of termination of your Account or of Service(s) associated with your Account, no credit (such as for unused Services, unused subscription period, unused points or Ubisoft Virtual Currency) will be credited to you or converted into cash or any other form of reimbursement.

Source