Presumably this checkbox is equivalent to the /define:TRACE compiler option. You might want to turn this option off for a release build either because you don’t want end users to see the trace output for some reason (e.g. security), or to improve performance. Of course, the performance increase will depend on how much work is being done when it’s on, but the Conditional attribute will cause the compiler to completely remove the function call (including any string formatting, etc.) from the generated IL, so it could make a significant difference.