Difference in purpose
Unlike previous architectures like the gothic style architectures that were previously built all around Germany, the new Bauhaus style architecture were designed based on social, artistic, practical features. As seen in previous architectures, like the gothic style architectures, those pieces of architectures were heavily based around ornaments and decorations to make the architectures look as beautiful and decorative as possible. However, with the Bauhaus style architecture, things were different. Bauhaus architectures designed buildings to be sustainable, sensible, simple. Bauhaus movement teaches architects "truth to material", meaning that materials should be used in their most "honest" and appropriate form. For example, supportive things like steel should be shown off for other people to see and not hidden unlike the old style of architecture which focused more on decoration. Here is a video of some famous examples of Bauhaus style architectures, in the video it can be seen that materials like steel are presentable in the architecture instead of being hidden.