What's the difference between in-memory and traditional marketing software?

As development lead for campaign management (aka Acquisition), I often get asked why SAP has decided to build S/4HANA Marketing Cloud and SAP Hybris Marketing as a new solution on SAP HANA instead of just enhancing the existing SAP marketing solutions, or what's the big deal behind using SAP HANA as the platform compared to traditional marketing solutions.

Here you find my answers and a couple of videos which give a good insight on why the solution is unique on the market.