Idc, if i don't sell it for 1:10 I'd rather keep it. And the ppl who trade for 1:7 mostly don't deliver and have smaller quantities..
Which is quite essential when, for example u send ur troops to attack and ur village gets attacked. Then you can go and pick up 5k gold somewhere and pay 1:7 if you can make it back in time or you can buy 30k so you can actually buy some decent gear and get it delivered.. Might be worth 3 extra.