Why the Secret Spell Scroll system would have never worked.

Legitimate players sometimes need to buy or sell items worth more than max meso.
SSS are a convenient way to do such trades in one go, preventing possible scamming.

OT: This is why we can't have nice things.

This is sort of an overzealous statement but at this point I don't feel like legitimate players would even enter the free market because there are so many duped/exploited items that it's not worth the risk.