it gives a good indication because hes a defender and a defenders points come from clean sheets - that may not be down to him but he is part of the defensive unit that earns the points. As for meaningless points because a player might be useless for 89 mins i agree, look at Yak for example. But, it takes a second to score a goal and goals win games. If he wins a game after standing around for 89 mins but nods a goal in, does that make him meaningless?
I dont get to see him play every week but i see the points he gets me each week, so based on that (no matter how flimsy an argument) ive got to say hes a decent player....
edit: im a little drunk after a bottle of white wine and a few G+Ts, logic may be a little flawed.....