Why BTC/LTC exclusively for goods in the forum

[cryptoderf]

I see a lot of people asking only for BTC/LTC, not accepting others. Do not get me wrong, I think encouraging the use of net coins is in the interest of miners. But why bothering or sticking to it since :

1. You need an escrow to get security, so there is fee involved
2. You'll probably have more fees to withdraw anyway (most likely)
3. BTC/LTC values are swinging much more than real currencies. So it's an additional risk.