Since Project Orion 2.0 using Foundation is completely optional. We made separate training videos for Foundation or native Spigot API in Weeks 1-5. The Foundation build system is a library and a build setup which, we believe, makes you code faster.
Foundation adds the magic @AutoRegister annotation to register everything automatically and makes it super fast to create GUI, menus, command systems and custom entities. It replaces many complicated calls with plain English, simple one-word methods. And lastly, it makes your plugin work on all MC versions down to 1.7.10 (and 1.8.8) without you having to change your code at all!
We recommend doing what Tijn did; he started the course using Foundation; followed our advice without ego, and in built his own, unique system. He’s now fully independent, does not use Foundation, and got there faster than if he’d tried doing the same on Day 1.
That’s how people lose motivation. They stare a blank screen and waste time.
If you have a special need or absolutely not want to follow our system, our training videos show you both — with, and without Foundation — but we strongly urge you to at least give it a try for the first month of coding before dropping it completely. You’ll become independent, faster!