Thanks for the questions Tex_kol.
The short answer is that we haven’t changed the terms of the UE4 EULA in any way; if you were able to do something under the UE4 EULA before the launch of Unreal Studio, you are still able to do that under the UE4 EULA. Access to UE4 under the UE4 EULA is still free, subject to a 5% royalty on gross revenues if you are commercializing/monetizing a product. Even for commercialized or monetized products, there are several exceptions from royalties, such as for products that are entirely non-interactive or linear (which covers quite a bit of archviz).
Unreal Studio provides another way to access UE4 and comes with some tools that we hope our licensees find useful, such as Datasmith. The Unreal Studio EULA has no royalties, but after the end of the open beta will have a subscription cost.
Many architecture students and professionals are using UE4 under the Unreal Studio EULA, but many are also using UE4 under the UE4 EULA. Under both the UE4 EULA and the Unreal Studio EULA, there is no special costs for students or architecture professionals.
If you were happy with the UE4 EULA before, you are welcome to continue using it. If you need access to the tools and services of Unreal Studio, or need the certainty of a royalty free license, we encourage you to try out Unreal Studio.