Is it? $10 a day is $300 per month. Depending on price, electricity bills could be $15-30 per month, so a net earning of ~$270 per month.
Now, let's say that guy bought his card at the initial price months ago. He would have it paid off within three months of mining. For clicking a button. Seems like a fine return to me.
Of course with one single card you're not gonna make a living, that's for sure. But you're not risking anything like people who's investing thousands of dollars in buying overpriced cards are doing right now and you get some extra money for 'free'.
I'm currently mining with a shitty single GTX 1060 that I bought four years ago. That's $2 a day. But since I no longer play any game, it's either that or let the card run on idle forever. Last month I got €75. It's not much, but it's better than €0.