Except as a developer I lose lots of time if I have to wait long for my code (esp. Unit tests) to run. Having said that larger projects in C/C++ are often very slow to build (esp. if dependencies are not well defined and certain header files affect huge numbers of source files - a problem that doesn't exist with higher level languages). But even if using a particular language and framework saves developer time, it rarely seems to translate into developers using that saved time to bother optimizing where it might really count.