Rarely ever do you get one party control of all 3 branches of government at the federal level, causing the legislative process to be adversarial. The effect of this causes a lot of people to feel like government doesn't work and their votes don't really matter. Because of course we are a minority in respect to national elections. So in some areas, voting for senator is very important and you may be in a strong enough population to influence that election. In my state (Ohio) not so much. But local government? That's a whole different ball game. And if people voted at the local level they could build that habit of voting in general and maybe more people can feel like they are part of the process. But voting on the national level can be hard for black voters depending on where they live. I'm not saying their vote doesn't count because I still believe they should vote and push their friends and family to vote too.