It is actually a wage, that time isn't free. You could get a job at McDonalds for 1-2 weeks of the year and make the same amount of money in probably a lot less time.
I would not enjoy that work at all. On the other hand finding items with good spread and daily swing is a fun meta game on its own. So no, that's not even close to a wage. More of small time gambling.
Alternative take: it is about making money but paid labor is an exchange in return for money and what you put in is more than just time and effort.
If you like your job, your cost looks very different from doing an equally demanding job you hate. The emotional cost is real and can have long-term effects on your health.
Plus of course clicking stuff on your computer is something you can do in your time wherever you are as long as you have an Internet connection. Working for 1-2 hours at a gas station (or McDonald's or whatever) requires a fixed schedule and commuting, not to mention that you'd likely need to agree to a minimum number of working hours and are unable to just skip it whenever you want.
"Why don't you do this other form of unskilled labor for minimum wage instead" is a legitimate question when the current alternative is time consuming and they're struggling to make ends meet. Not so much when it's something they do for fun every now and then while already holding a job that pays above minimum wage.
