I might. There are 3 reasons:
* Money. This doesn't matter much too me, but it might for people who make a lot less than me. The comment I replied to was about anything less than $10, not about $1 specifically.
* Preventing future scams. By doing a chargeback against scammers, you're making it more likely they'll get banned. So you're helping to prevent other people from getting scammed in the future. It's a good deed. When I see phishing sites, I report them. Why wouldn't I report a scam?
* Revenge. Some people want to see the bad guys get punished.