Let’s watch a blitz game played by IM Anna Rudolf with black pieces (starting at 4:48) where Anna shows Queen’s indian defense 1. d4 Nf6 2. c4 e6 3. Nf3 g6 4. Bg5 h6 5. Bh4 Bb7 6. a3 Be7.
We can see a solid defense. As Anna Rudolf mentoins in the video all the pieces are kept (collected) in 3 rows therefore she goes for d5 and gets some space.