On its face, that makes some intuitive sense. I'm more worried about jobs and the economy than campaign finance and I work in campaign finance.
The real questions are what do you do with the information about voter sentiment and how does it arise for voters in context? For example, if you put the issue directly in front of them, what result? Or does it mean you can or should let these laws fall into desuetude (as some suggest) because you've concluded voters don't care, as Cillizza suggests, or don't understand.
More broadly, the support for these reforms seems to suggest voters do understand the importance of campaign finance. They should. After all, the folks heavily involved in financing campaigns care a lot. If businesses, unions and others are voting with their pocket books, literally, it's because they're interested in policy outcomes.
And voters, who care about jobs and the economy and other issues, do too. But if you don't know where the cash is coming from you don't have a complete picture of why the policies are what they are or whether politicians are acting in the public's interest. So campaign finance really encompasses all issues. Not just one. That's why it matters. And it matters to voters.