Sometimes, for a while, at small dollar amounts. The 0% intro card is what people reach for before they have a home equity line of credit, and it does one part of the job well and two parts badly.
Start with what it does well. A credit card has a grace period, which means purchases made in one statement cycle accrue no interest as long as you pay the statement balance in full by the due date. Run the household's groceries, gas, and utilities through the card, keep the paycheck parked where it's offsetting interest, and pay the card in full every month. The float is real, and the credit card grace period, used on purpose covers how to set it up.
Now the two parts it does badly. The first is getting cash out. A line of credit lets you write a check or wire money. A credit card doesn't, at least not cheaply. A cash advance charges a fee of 3% to 5% up front, starts accruing interest the same day with no grace period, and usually carries a higher rate than purchases do. A balance transfer moves debt from one card to another for a fee in that same 3% to 5% range, which is fine when you're refinancing a balance and useless when you're trying to send $20,000 to a mortgage servicer. Most servicers won't take a credit card at all.
The second is that 0% ends. Intro windows run 12 to 21 months and then the card reverts to its regular rate, which on most cards is well into the twenties. Miss a payment and many issuers can end the promotion early. A home equity line of credit priced at prime plus a margin is a rate that moves, and it moves a point or two, not fifteen. Your HELOC rate is prime plus a margin explains which half of that ever moves.
Run the number before you decide it's cheap. A 3% transfer fee on $15,000 is $450. Spread across an 18-month 0% window, that works out to roughly 2% a year. Against a card charging 24%, that's a good trade and you should take it. Against a home equity line of credit at 8%, it's still a good trade for those 18 months. The problem is month 19 if the balance isn't gone, because the fee was already paid and the rate that replaces the 0% is the worst rate in your wallet. I went through whether it makes sense to just roll balances onto a new card every year in a video on annual balance transfers, and it comes down to whether you have a payoff date or only a habit.
So the place for a 0% card in a Dynamic Banking plan is as a short-term tool aimed at one specific balance with a payoff date you've already written down. It isn't the hub. The hub has to be something you can pull real money out of, at a rate that doesn't jump fifteen points on a calendar date, with a limit the issuer isn't going to cut the month your utilization spikes. Card issuers reduce limits, and they do it fast and with little warning. Lenders can freeze a line of credit too, and who can close your line of credit covers when that happens.
If you don't have a home equity line of credit and don't want one, a personal line of credit from a credit union does the cash part a card can't. Usually unsecured, usually priced between a card and a HELOC, and you can draw real money off it the way Dynamic Banking needs. HELOC or personal line of credit compares the two.
Use the card for what it's built for: the monthly spending you were going to do anyway, paid in full every cycle. Then keep the chunking money somewhere it can leave the account as an actual check.