All that is true, except the big kicker is since Sudan is a member of the UN, the UN can order sanctions against them. Sudan refusing the warrant and not abiding by UN directives will trigger punitive actions withing the UN. Not a big deal for a major country like US, china, russia or isreal, but Sudan needs UN loans, UN food programs, UN aid programs, etc. This will also snowball into IMF and World Bank sanctions. And sanctions against any other member nations who attempt to go around the sanctions,( like Shell oil who have supported the thug gov't so they can pump oil). In effect making the Sudan an international pariah.
It's a long game gamble, but there has been no other real action on Sudan, so I guess this is the best they could do. Sudan immediately responded by kicking out UN aid workers to show they don't need the help, which of course they do. Time is running out for Sudan. The only question is if there will be anyone left when it's all over.