I've always wondered what the hell these people do with all that space. I live in a 700sqft apartment and even that feels excessive (albeit living alone). If I had unlimited money and owned that mansion, I'd run out of ideas before making use of even 25% of the building.
I dont think I could live like these people even if I had the money; I feel like I hate the idea of having people whos relationship is purely professional going around in my space to clean things, but trying to clean all that space by oneself without hiring people to help sounds like a lot of bother.
You'd probably have them only stop by when you're out, and you'd be out of the house most of the day anyway. You'd just be alone. But imagine there always being snacks and drinks, and you can eat any food just by ordering it, and being able to invite people over whenever you want without worrying about them making a mess. It'd be a fine situation even for introverts.
I'd have a lego room, a statue room, a game room, a recording studio, an indoor garden for year-round fresh veggies and beans, a gym, a whole network of model trains running the whole house. Yeah I could probably use a lot of the space. Though to be honest I have a very small space now and I am extremely happy with it, I certainly don't need more than what I have.
Also some intruder could be living in there with you without your knowledge. That's my irrational fear about large homes like this, too many places for someone with bad intentions to hide.