So in theory to keep the flat you have to fuck ten guys a month for free before you earn a penny. If you can work from home you can afford to see ten less people a month (and have that time to do other things, work more, do whatever you like) and earn exactly the same money.
If you can work from home and see enough people to make it worth it I say go for it! I'm all for keeping overheads down. If nothing else, it takes some stress off, knowing you are in profit much faster, straight away really if you work from home.
I don't work from home but I'm sure some ladies have good cover stories for people coming and going. There are obviously advantages to both working from home and to having a work flat but if you need to cut costs, I'd say work from home for a while, if you can of course. You can always rent another flat if you need to.