I am studying group theory by myself and while i was reading "Physics from symmetry", Jakob Schwichtenberg's book, he said it was conventional in physics to write the generators of SO(3)$SO(3)$ with an extra $i$, that is, multiplying the group generator matrix by $i$, but i am not understanding is why the generators have to be written like that? with the $i$, why this is conventional? what is the advantage?
In physics it’s conventional to define the generators of $SO ( 3)$ with an extra $i$. Concretely this means that instead of $e^{φ̃J}$ , we write $e^{iφJ}$ with with φ = − φ̃.
This is the quote that i am referring to in my question, right below equation 3.70, page 44.