Money aside, that building is a marketing vehicle. It's meant to show Apple in the posh, advanced, and sustainable light it wants to be seen (whether that image is true or not is another question, but such is marketing).

It was also built to draw in new talent, but in a pandemic it's probably not the attractor they hoped it would be. I doubt Cook is losing sleep over it, but the pandemic definitely messed with his long term plans (like most everyone else, of course).