However, in general yes - a 30% haircut on laundered money isn't too bad at all. Consider the classic money laundering scheme: you own a legitimate bar, but supplement the real sales with ghost sales, paid for by the dirty cash. The alcohol supposedly sold in the ghost sales is poured down the drain, so your suppliers invoices match up with your sales (this works because it's typical for customers at bars to pay in cash, and the margin on alcohol sold as individual drinks is pretty high).
But they exist, and they're huge. Obviously merchants love them for the float and captive customer spending more than the gift card balance. Businesses might love them to give out to employees since it's not taxed income, and similarly, money launderers would like them.
I guess I could see some niche use, like wanting to give a child funds for a movie ticket, but to avoid them using it for other purposes you restrict it by giving a movie gift card. But I don't see that supporting a large market.
Giftcards are seen as a way around that (although they’re not really better). They also show that you thought about the gifted (what would this person like), but respect that they might not like the specific gift you’d pick.
e.g. if you know someone is a LEGO collector, you gift them a LEGO gift card, instead of buying a specific collectors model that they might already have.
The article is not about money laundering, but using stolen credit cards. It makes little sense to use Amazon for laundering.