When using the MATLAB Compiler to compile MATLAB code into a standalone executable, you do need to install the MCR because the generated code calls into these runtime libraries. Also, you can package the MCR together with the executable and have it installed automatically when the executable is run. If you are using deploytool, you simply need to select "Add MCR" and "Embed the MCR in the package" from the Package pane.
Note that MATLAB Coder is the other product that actually allows you to generate truly standalone C/C++ code from MATLAB code (without any need for additional libraries like the MCR). However, it supports only a limited subset of the MATLAB language.
