Breakdown of Wozu brauchst du das alles?
du
you (informal singular)
brauchen
to need
alles
everything
wozu
what for, why
Questions & Answers about Wozu brauchst du das alles?
Why does this sentence use wozu instead of wofür?
Both are possible here, but they have a slight difference in focus. Wofür asks specifically what the object is dedicated to, matching the preposition in etwas für etwas brauchen. Wozu asks more broadly about the purpose or intended goal, meaning roughly to what end or for what purpose. In everyday spoken German, wozu is extremely common when asking why someone needs something.
How does the question word wozu relate to the hier- compounds we are currently learning, like hierzu?
Wozu is the interrogative question word asking for what?, while hierzu is a proximate pronominal adverb meaning for this right here. If someone asks Wozu brauchst du das alles?, you could point to the project directly in front of you and answer Ich brauche es hierzu, meaning you need it for the specific task at hand.
Why is the word order das alles instead of alles das?
In English we say all that, putting the word all first. In German, when words like alles, alle, or beide refer to a pronoun, they usually follow it directly. This is why we say das alles for all that, wir alle for all of us, and ihr beide for both of you.
Is it ever possible to split wozu into two words in spoken German?