The sense is that if someone thinks your item is really good and doesnt want to wait 12 hrs to get it, he can buy it now.
Also with the bidding you are not really sure that you will get the item, with the buy now, you can have it for certain
ok...but this concerns the items, that I would like to buy from other player. But if I give on auction an item for sell - should I have tha chance to buy it with for example "buy now" option?
I see in it only reason, if somebody makes mistake and want to change the price. He pays the commision tax, and then he can sell for different price.