No. Don’t commingle personal funds and credit cards with the startup’s credit cards and accounts. Even if you are going to miss out on points or convenience, it’s a bad idea to commingle.
This is a thing that the IRS would look at if they ever audit your startup. So you don’t want money moving back and forth and getting mixed up between a personal and business expense.
It will also make accounting a lot harder. And heaven forbid something looks off to one of your venture capital investors; you don’t want anyone to ever doubt that you are doing the right thing for the startup’s finances. Even if you are not doing anything odd, introducing doubt is a bad idea. Remember that as CEO, you are a fiduciary for your investors’ capital and the business. Don’t put the business at risk.