Excel has always been associated with office work and spreadsheets (and less associated with the oh-so-cool production of artwork) which are long, mundane, repetitive tasks that we try to, but can never seem to be able to, avoid doing. That’s why time-saving tricks and shortcuts are great hacks
This is a very masculine home office. Torvald is always in his office working, so this represents him. I would imagine that his office looks somewhat like this. He locks himself in his office a lot and works. Since he is wealthy, his office would be decorated with intricate things like this.