I'm coming at this from both sides. Yes, I am feeling a bit sore that dd has had a poor effort grade in a couple of subjects. But it's not just that. I used to get brilliant effort grades in subjects I found easy. It looked as if I was working hard-actually I was coasting. And for the things I found hard and really tried in? Rubbish effort grades.
You can grade application, attentiveness in class, all sorts. But you've no idea of knowing how hard stuff is for someone, nor how hard they're working. Ironically, dd had a brilliant effort grade for the thing I know is effortless for her. What is hard for her is sitting still, listening, breaking up a task and not panicking at the sight of it and not procrastinating over it. I know-I've worked really hard with her on this at home and, although she's still not heads down no fuss, she gets on with the homework and gets it done.
I'm not about to storm the school gates. But the other thing is that it is assumed she could just go "oh-poor effort grade, best pull my socks up" which I don't think is true. Any more than someone struggling with maths can go "oops - best get better at maths then". There's people who are naturally good at achieving, there are those who are naturally good at applying themselves. At the opposite ends, support is needed.