Agree but the problem comes down to WHY you need experience. Football clubs want experienced players because they know how to handle themselves when the going gets tough unlike the younger ones who can be prone to being mentally weak, or at least that is the common justification.
The issue here is that Barton, despite being highly experienced, is mentally weak himself and at the most inopportune moment can get himself sent off, go flying in rashly to try and catch a player on the counter who he misses and leaves through on goal, or often just winds up people on the pitch in situations where they don't need to be wound up and the extra motivation that comes with that.
For all intents and purposes he is a child in a man's body so the only reason you'd take him is because of the football player rather than the football man that he is. Barton isn't a good enough football player to play for a West Ham looking at moving towards those top six spots and is a stopgap at very best. His Hollywood-type long balls are extremely frustrating for a team famous for playing it on the ground, he is defensively dumb ala Scott Parker rather than Michael Carrick and whilst he has a great strike on him, he doesn't offer enough of an attacking threat to be called somebody who would have a style built around them. He should have gone to Villa or somebody of that ilk, not only is he bad news off the pitch but I cannot see what he'd bring to you on it.