This is definitely a lot of fun. Your Sim can fail at a gig, and there are some humorous results (being told that you'll be featured on Failures & Flops is one).
As people have pointed out, you could do this yourself, giving yourself the challenge of changing a room to meet the likes and dislikes of the Sims in the house. What distinguishes the pack is that you get feedback from the Sims. When my Sim renovated a room for the Partihaus household, she got a handshake from Paolo Rocca, hugs from Jade and Marcus (also tears of joy from Jade), and Eva jumped up and clicked her heels. It's nice to be appreciated, and from now on, I'm not making any changes to any pre-made houses except through my Sim as an interior designer.