That's like saying I payed for my new house with stocks. Which is not the same thing as stocks being a currency. What actually happened is that you liquidated some crypto and used the proceeds to buy your new computer. You even say that directly in your parenthetical. (since I converted some crypto to do it)
I converted from one form of cryptocurrency to another cryptocurrency (USDC is USDCoin, a Stablecoin).
I was paying on NewEgg using their BitPay method, which supports payment with only the following cryptocurrencies: Bitcoin, Bitcoin Cash, Ethereum, Wrapped Bitcoin, Dogecoin, and 5 stablecoins (GUSD, USDC, PAX, DAI, and BUSD).
I have Bitcoin and could have paid directly with that, but I wanted to keep holding it and pay with Litecoin. So I converted that to USDC (for free, but I will have to pay taxes on the gains next year since every conversion or purchase is a taxable event in crypto in the US), and then sent that to Bitpay.
So yes, I still maintain I used USDC for its intended purpose.
I did, however, do what you said and liquidated some Ethereum to fiat several years ago (right at the previous bull run's top, by happenstance, got super lucky then) to pay for the downpayment on my home. I would have paid with it directly if I could but there was just no mechanism for it, at least not back then.
