Gandalf thought Bilbo to be a suitable companion to Thorin and his Dwarves for a number of reasons. First, he had observed that Bilbo took more of an interest in the world at large than was usual for hobbits, and was thus more likely to be adventurous. Another reason was that Smaug would not recognize the scent of a hobbit, advantageous to a stealthy operation and likely to distract the dragon's attention. Finally, Gandalf thought that putting a hobbit in the company would prevent Thorin, who did not think much of hobbits and doubted Bilbo's skills, from doing anything rash, such as openly confronting Smaug.