A combination of both methods work well,if strategically managing a portion of your overall portfolio for trading allows you to invest for growth over the longer term.
I love your conclusion on this. If it were to be some people, they might outrightly choose one over the other for obvious reasons of what they have to offer, but it is good to diversity. Why not try trading? Why not try investing? Both are means of making money and people are making money through them, even though trading is risker, and investing is less risky. Nevertheless, engaging in the two will surely average it. And if trading becomes a headache, you leave it and focus on investing. No one can be prosecuted for trying, it is lack of trying that is even worse.