By it self not much, its just running the blockchain like the wallet used now, but it will be the backbone on which the stratis ecosystem is build.
It is basicly just a shift to the C# programming language. For basic users it wont really make a difference but for the stratis devs it means that they can start working on delivering all the promised features.
Other devs should also be able to start working on projects that will run on the stratis blockchain.