A program having multiple functions is considered better designed than a program without any functions because:
- Program handling becomes easier: Only a small part of the program is dealt with at a time.
- Code reusability: A Python function can be defined once and used many times. So, it results in code reuse, we don't need to write the same code more than once.
- Compact code: While working with functions, a common set of code is written only once and can be called from any part of the program which reduces lines of code and programming overheads.
- Easy updation: If we need to update a formula or expression, changes must be made everywhere it's used, risking errors. Using functions simplifies this by making changes in only one place (which is function itself).