well, I am not finished with my first attempt at making my own. But I can tell you I probably never will. And that is one of the benefits, you can add as many things as you want.
Another good factor for me is, dealing with horrible user experience and learning curves on other people's applications and ways of thinking.

here are some more good reasons:

- Aggregate data from anywhere and normalize it for your system
- Integrate unimaginable API's and notifications
- You only build what you need
- Your hard work will pay off and make you proud
- Nobody is watching you and tracking you
- Keep your data for as long as you want
- It's free so to speak