I don't see any issue putting materials on a credit card. I know a lot of people who do it both inside and outside the construction industry. Some people I know do this for the miles or rewards. You may also consider opening charge accounts with suppliers that offer terms. 10 days, 30 days, 60 days, whatever they can setup for you.
With subs, you'll need to have money in your account to pay them. I don't think a credit card is the best way to pay subs. Having money in your account could be from your operating capital reserve, taking a large enough deposit and having a correct payment schedule for your projects or having a credit line that you can utilize.
Paying yourself..... that's the fun one. Not charging enough for your work will leave you short of money to pay yourself and eventually your subs and materials. This is what we all have to keep in mind every day.