WikiSuite | WikiSuite vs Open-Xchange

Open-Xchange and WikiSuite have some similarities. This page is to explain the differences and rationale of choices. You likely will be interested in the other alternatives to WikiSuite.

Similarities

Both are enterprise suites

Differences

WikiSuite is fully Free / Libre / Open Source whereas for Open-Xchange, it's complicated. See their explanation

We have licensed our backend under a GPL2 license and our frontend under a CC BY-SA-NC license. In addition we use some 3rd Party components in the backend and frontend. Further information about the different licenses for these components can be found here: https://www.open-xchange.com/terms-and-conditions

You may not exercise any of the rights granted to You in Section 3 above in any manner that is primarily intended for or directed toward commercial advantage or private monetary compensation. The exchange of the Work for other copyrighted works by means of digital file-sharing or otherwise shall not be considered to be intended for or directed toward commercial advantage or private monetary compensation, provided there is no payment of any monetary compensation in connection with the exchange of copyrighted works.

Source: https://creativecommons.org/licenses/by-nc-sa/2.5/legalcode

Questions

Is there a realistic way to use back-end without using front-end? If not, the global solution is de facto in the most restrictive license.
Is there a scenario where a business can use? If the business sends out an email related to providing a service or getting paid, how does that not conflict with non-commercial clause?