Should I pay for a condo or major purchase with a credit card to get points if I have the cash?

Only if you can pay the credit card statement balance in full the next month, the merchant accepts credit cards without a surcharge, and the points value clearly exceeds any fees. Most large purchases (real estate, cars, jewelry) either do not accept credit cards or pass a 2-3% convenience fee to the buyer. That fee is almost always larger than the rewards value.

The math. A 2% rewards card on a $50,000 condo down payment earns $1,000 in rewards. If the title company or builder charges a 3% convenience fee for credit card payment, the fee is $1,500. You lose $500 net. If the merchant absorbs the fee, you net $1,000 in rewards minus any opportunity cost on the cash.

When this works. Some categories of large purchases accept credit cards without surcharge: tuition payments, IRS tax payments through certain processors (Pay1040, ACI Payments), business equipment from certain suppliers, and luxury retail (jewelry, watches, art). For these, paying with a high-value rewards card and immediately paying the statement in full from cash on hand can earn $500-$2,000 in points or cashback.

When this does not work. Real estate transactions almost universally either reject credit cards or pass through a 2.4%-3% surcharge. The same is true for car purchases above small dealer-cap amounts (typically $2,000-$5,000). The IRS allows credit card payments through third-party processors with a 1.85% to 1.98% fee; a 2% rewards card barely breaks even.

The opportunity cost. If you have $50,000 in cash and you pay it on a credit card to earn rewards, you need to pay the credit card statement balance from that same cash within 30 days to avoid 22% interest. You have not added cash to your life; you have just routed it through the credit card. The float advantage is small (one month of interest on the cash).

The trap. Paying a major purchase with a credit card with the intention to "pay it off later" usually does not work. A $50,000 charge on a credit card produces a minimum payment of about $1,500. If you cannot pay the full $50,000 within the grace period, the entire $50,000 starts accruing interest at 22%, costing $11,000 a year. No rewards rate beats that.

Better alternatives. For real estate, pay from a high-yield savings account and earn 4%-5% on the cash until closing. For tuition, consider a 529 plan distribution which has tax benefits no credit card can match. For business equipment, equipment financing typically offers 6%-9% rates, far better than a credit card carry. Use the credit card for routine spending where the rewards math is clean.

Specific products that make it work. Cards like the American Express Business Platinum, Chase Sapphire Reserve, and Capital One Venture X earn 1x-3x points on large purchases. If the points are worth ~2 cents each in travel redemption and the merchant absorbs the fee, you can effectively earn 2%-6% back on the purchase. But verify the merchant accepts cards at no fee before swiping.