(i) Ausable - characterised as short and fat as the writer wants to draw attention to and emphasise his wits and mental ability to handle any grave situation [Ausable was able to successfully plant a story of a non-existent balcony and also made the agile and smart Max believe it ---didn’t require an attractive physique to do this.]
(ii) The writer, perhaps, wanted to give a strong message that the brain is what counts more than brawn/ muscle power OR brain power is far more potent or effective than any other type of powermuscle or armsetc.