Having a work-dedicated space matters for a lot of reasons. For myself, sharing a desk between work laptop and home desktop means that I'm easily distracted by the Fun Shiny Toys, and for others (and for me if something really big goes pear-shaped) it means that it's hard to put the laptop down and step away to Home Space, because it's sitting Right There and I can always go back to it or "five more minutes." In general I'm very good about "these hours are for work and after these hours I do Not Work", but having it share space is tricky.