The explanatory text in this game doesn’t tend to be super clear…
That is the dilemma, for sure. And already in 3 responses you’ve gotten both opinions.
I think it ultimately comes down to play style, and to some degree intended use. Utility heroes supporting other heroes on a team need to stay alive. And the attackers need to hit hard.
Grimm could arguably be either one or both, which makes the decision a bit harder. (Unless you’re @Elpis.)
But like @Rigs said, you don’t have to rush to decide.
And there’s also the benefit that the first choice you make doesn’t preclude switching the build direction to balance differently later.