The sale of real life items presents a world of problems on Sythe. First of all, the actual process involved with shipping an item to someone else is a whole lot more complicated than sending money. The cost of shipping with tracking is expensive, especially when done internationally, and is exploitable. People will often use a tracking # scam, where they find the cheapest way to send a parcel with a tracking #. They then claim that because they have a valid tracking #, it proves they sent the item, when in reality they could have sent a piece of paper with a coffee stain on it for all you know.
The fact that nearly all items being sold in this way on Sythe would be used is another concern. If someone sends me an xbox, I receive it, but the xbox breaks 2 days after I receive it, who is responsible? If the person on the other end of the trade has received his gp for the xbox, he's not going to provide reimbursement. There is also the problem of stolen property. Stealing money is a lot trickier than taking your brother's gameboy, or your friend's walkman. People's belongings are usually much easier to nab than their money.
All in all, real item trades are just a whole world of trouble. Because of the ratio between successful and unsuccessful trades is so lop-sided, we decided to just bar them completely. This will not be changing, but if you wish to negotiate a trade like this privately with someone, go ahead. Just don't advertise it here, and don't expect any action to be taken on Sythe if you do get scammed.