: How is python useful if its not compiled and the person must have it installed to run the scripts?
It's actually far more "useful" precisely because it is not compiled. Well, also because the syntax is so simple. You can use it for tiny "shell scripts" all the way up to full-blown web frameworks.
And you can write extensions in C if you really need the performance boost for something.
Compared to the Java runtime or the mammoth .NET framework, the Python interpreter is a very modest thing to require users to install.
And technically, the code does get compiled, just like Java and .NET, to a "bytecode" file, which is what the interpreter actually executes.
$ select * from users where clue > 0
no rows returned