Other than it being non reversible, it is also pseudonymous. One can easily create an account to scam people and vanish into the thin air and the authorities will not bother with them at all. For banks, some of them allows transactions to be disputed. Without proof, the buyer will always win.
Yes, also I forgot to mention being non-reversible is a
good thing
![Smiley](https://bitcointalk.org/Smileys/default/smiley.gif)
This is because people often use reversible things like credit cards for fraud. They buy things they want then tell their credit card company it was a fraud charge or they didn't get what they thought from the business, which results in a chargeback to the business even though they sent the product! They lose money on that transaction and pass those operating costs onto other customers.
Being pseudonymous is also a good thing of course. It's not about doing anything illegal. It's about privacy. Some people might want to shop online and buy adult toys. That's perfectly legal, but maybe they don't want everyone knowing their business.