the government has given the go-ahead for the first step towards complete digital sovereignty in the state, with further steps to follow.

The term digital sovereignty is very important here. If a public administration uses proprietary, closed software that can’t be studied or modified, it is very difficult to know what happens to users’ data:

We have no influence on the operating processes of such [proprietary] solutions and the handling of data, including a possible outflow of data to third countries. As a state, we have a great responsibility towards our citizens and companies to ensure that their data is kept safe with us and we must ensure that we are always in control of the IT solutions we use and that we can act independently as a state.

Digital sovereignty seems to be the primary impetus, so this might go far. Saving money is secondary.