What part is non-standard? They generate standard Visual Studio projects. Ctrl-B in Visual Studio still builds the project. Seems pretty standard to me. (If you think “generated visual studio projects instead of carefully hand-crafted manual project puzzles” is non-standard, I disagree – every place I’ve been at that uses Visual Studio, uses some tool to generate the projects.)
Using a tool that parses some source files and generates some other source files is also pretty standard in industry. Almost every compiler in the world uses some kind of grammar/lexer tool or library to describe the language at a higher layer and generate source code to execute it. Tools like lex/yacc or flex/bison or ANTLR are frequently used similarly to the unreal header tool.
Now, do I sometimes have frustrations with build setup? HECK YES! Because, standard or not, build systems are generally second-rate citizens in most organizations, and don’t receive the tender care and love that the main codebase does. Which is a shame. That’s not a result of “non-standard,” as much as it is a result of most engineers not being build engineers (or most organizations not prioritizing/promoting build engineering.)