They are almost the same just as Daniel mentioned. The main difference is just as what you have found: Visual Studio Build step add Visual Studio Version to the build.
Should I use the Visual Studio Build step or the MSBuild step?
If you are building a solution, in most cases you should use the
Visual Studio Build step. This step automatically:
Sets the /p:VisualStudioVersion property for you. This forces MSBuild to use a particular set of targets that increase the
likelihood of a successful build.Specifies the MSBuild version argument.
In some cases you might need to use the MSBuild step. For example, you
should use it if you are building code projects apart from a solution.