I was thinking of mining just to make up the cost of the card too, but the card cannot be used for games while mining, and you have to pay short-term capital gains tax when you sell the ETH, which may be significant depending on your income. You also end up speculating on the price of ETH, and it may fall over 3-4 months (like it did today). I find that when you take all that together, it's not really worth the effort anymore for just one card.
Unless you're 1% type rich I don't see how it's not worth anyone's time. $441,451 a year is a 20%, , $40,001-$441,450 is 15%, and $40,000 or below is 0%.
I literally spent less than 30 minutes setting everything up to make $400 a month. Even if you make $500,000 a year and you spend maybe 2 hours a year configuring your miner (I spent only 10 minutes tops setting up my wallet and miner)
that's $1,920 an hour for the effort put into it ( 12month X $400 X 0.5 X 0.8 ).
True that you can't game while you mine. I'm no longer in my late teens or early twenties where I play games 16 hours a day. Outside of this past year I'm lucky if I can play 8 hours a week.
And sure the value of crypto currencies is going to fluctuate. I'm not some day trader in the crypto currency market. I'm going to keep mining until the card is paid off and then until I have one entire Ethereum coin, that or until the make my computer ineffective. But even if I was a day trader, I bought the card so I could have the best GPU money could buy for VR. Anything else is secondary. It would be like someone offering you money to download some files and plug a USB stick into your TV.
TDLR: Unless you're a Bill Gates type it's worth your time since it takes less than a hour to set everything up to make hundreds a month for clicking a button a few times a year.