You can think of the first basic meaning 버티다 bears, which is rather comparable to how "hold" and "stand" have've got another meaning "endure" have in English. Like this, 버티다 rather has focus on actions against, while 견디다 is a little more abstract, I reckon. Like he said you can use both the same way

거의 같아요, 그런데 견디다는 좀 어떤 힘든 상황에서 참고 지낸다의 의미이고, 버티다는 구체적인 상대방이 있거나, 그런 상태와 싸워 이기고 말겠다는 의지가 포함되어있다고 봅니다.