Most likely people were being paranoid about their grinding location becoming known.
Also, there's an auto-return function in case a player die he/she would return to his/her previous grinding spot.
It's a great option if one is farming in higher level maps because there's a slim chance that the mobs might kill them but enemies often exploit this one, especially in wars as they could kill the player over and over again while afk. There's 3x free restore available everyday but if one was killed multiple times say more than 15 then leveling would be greatly delayed. There's also a penalty for internal injury like deduction on experience gained for long hours so that really sucks.