Difficult question, actually, in a way!
I want to agree, and you could even perhaps say that it would be difficult to disagree, and yet … and yet … and yet … the problem, here, is that agreeing with it tends to lead to a discussion about the “lot more to it”.
And that can be really misleading for people who are learning, because in practice it necessarily focuses their attention on the less important aspects (with which they tend to be more comfortable), rather than helping them a little more actively and realistically by repeatedly drilling into them - even more or less to the exclusion of everything else at first - that they MUST start from a strategy that has a proven edge.
And that means knowing what a proven edge is, and how to tell whether or not what you’re doing has one.
And that’s really difficult for most people to learn!
But - especially in the early stages - anything else is just a distraction from that. And if people don’t focus on that first, and master it first, they’re just not going to be able to trade profitably for the long term.
And the long term is all that matters, in this game, isn’t it?
So this issue and how you approach it, and what you emphasize, are actually a pretty Big Deal in the overall scheme of things, you know?
Don’t lose sight of how right, and how important, what the Herring and our pink-hatted friend are saying is. Even though there’s a lot more to it, too.
Shifting your attention to the “whole lot more” without first mastering the edge components (no mean feat!) is a huge and very common mistake from which, in practice, very few people ever recover. 
These things really do matter! 