Creating standalone executables is a commonly overlooked topic in materials that cover packaging of Python code. This is mainly because Python lacks proper tools in its standard library that could allow programmers to create simple executables that could be run by users without the need to install the Python interpreter.
Compiled languages have a big advantage over Python in that they allow you to create an executable application for the given system architecture that could be run by users in a way that does not require from them any knowledge of the underlying technology. Python code, when distributed as a package, requires the Python interpreter in order to be run. This creates a big inconvenience for users who do not have enough technical proficiency.
Developer-friendly operating systems, such as macOS or most Linux distributions, come with Python interpreter preinstalled. So, for their users, the Python-based application still could be distributed as a source package that relies on a specific interpreter directive in the main script file that is popularly called shebang. For most of Python applications, this takes the following form:
#!/usr/bin/env python
Such directive when used as a first line of script will mark it to be interpreted in the default Python version for the given environment. This can, of course, take a more detailed form that requires a specific Python version such as python3.4, python3, python2 and so on. Note that this will work in most popular POSIX systems, but isn't portable at all. This solution relies on the existence of specific Python versions and also the availability of an env executable exactly at /usr/bin/env. Both of these assumptions may fail on some operating systems. Also, shebang will not work on Windows at all. Additionally, bootstrapping of the Python environment on Windows can be a challenge even for experienced developers, so you cannot expect that nontechnical users will be able to do that by themselves.
The other thing to consider is the simple user experience in the desktop environment. Users usually expect that applications can be run from the desktop by simply clicking on them. Not every desktop environment will support that with Python applications distributed as a source.
So it would be best if we are able to create a binary distribution that would work as any other compiled executable. Fortunately, it is possible to create an executable that has both the Python interpreter and our project embedded. This allows users to open our application without caring about Python or any other dependency.
Let's see when standalone executables are useful.