Here are some helpful features of the Connected Applications technology:
1. You are creating the testing scripts in your favorite IDE using its editor and debugger.
2. You can use functions and types of the IDE you are working in.
3. If you embed your tests in the tested application (so it became a so-called self-testing application), you'll be able to access classes, objects, methods and constants of your application from the testing script even if they are not accessible from TestComplete.
4. If you are creating a script for some third-party company, you have the ability to ship only the compiled executable file in order to protect your code from unauthorized access/change.