CMAKE_EXECUTABLE_SUFFIX corresponds to executable suffix on target platform but it can be something completely different from the executable suffix in the host's environment. For example, CMAKE_EXECUTABLE_SUFFIX when building for Emscripten can be either .html or .js. Other examples, cross-compiling for Windows on Linux and vice versa.

Having single CMAKE_EXECUTABLE_SUFFIX (without CMAKE_HOST_EXECUTABLE_SUFFIX) makes it difficult to maintain consistent find_program(FOO_COMMNAD "foo${CMAKE_EXECUTABLE_SUFFIX}") for host programs.