Frank is a horseman, Emma is not.

Emma's guesses about the Frank Churchill she had never met, seem very consistant with him.
"he can adapt his conversation to the taste of every body, and has the power as well as the wish of being universally agreeable. To you, he will talk of farming; to me, of drawing or music; and so on to every body, having that general information on all subjects which will enable him to follow the lead, or take the lead, just as propriety may require, and to speak extremely well on each;"
And he certainly has become a treasure at Highbury. We do not often look upon fine young men, well-bred and agreeable....