Phones can be diverted but when my last employer tried that it always rang when I was on the bog.
As for the tea making ~ I never suffered from a shortage of tea when working at home.
The biggest (serious for a moment) problem was (and I suspect still is) that most employers (managers) are control freaks who cannot stand the thought that you are out of their sight and thus out of their control.
Despite a senior rank and more service than most whenever I was out of the office my MD would find "reasons" to call me to find out "How the figures look today" or "Who is it you are meeting today" or "You looked a bit down last night in the pub ~ everything OK?" Pure control freakery!
Now remember that my job was as a sales manager thus my task was to go out and seek clients, talk to them, assess their needs, design and present costed solutions for those needs at a profit to my employer so it was annoying to say the least to be pursued around the country by this maniac who wanted to know where I was every minute of the day.
In the end, whenever he was out of the office and I or one of my colleagues was in we took to ringing him asking the most inane questions about company policy and the like. He never did get the message and in fact our scheme backfired as he became even more convinced of his own indispensibility. Eventually the board got shot of him and we got a better MD who understood that if left alone we worked better and produced results ~ after all no salesman is of any more value than the profit on his last sale.