Jiang Wang chose a detour because the distance to the Floating Island was so great that it afforded no safety. However, to Jiang Wang, Granny Bizhu posed a greater danger than the Sea Clan.
Although the Sea Clan was certainly much stronger, after all, they didn't know who he, Jiang Wang, was, and wouldn't specifically target him unless they stumbled upon him.
He needed to familiarize himself with this place and, ideally, have traps set in advance to gain the advantage of terrain.
Just like the time he chose to wait for Hai Zongming at Camel Hump Mountain to greatly weaken the power of his Water Taoism Technique.
He was certain that Granny Bizhu was waiting for him in the inner area, while he was lying in wait for Granny Bizhu in the outer area.
It was a gamble.
