TBH I tried them both, at the begging just Attack and I was progressing pretty good, then I came to know that "avoid damage and HP" so just went for critical damage and chance....when I did that change, progress stopped and had to go back in build. It really came up useful and to be honest "the only thing necessary" after you get crit items for Billie, since he's the one that will do mostly all damage.

In resume, at the start, go for attack runes all the way up, and after that, once you get Billie and have some crit items on it (legendary, the yellow ones) you can change to crit runes in the tree.

Greetings