I've co-owned a small co-working space for about a year now. It's been a good decision, financially. Nothing extravagant, but I certainly have no regrets and I'd invest in another if the opportunity came up.
One thing that I think helps is that historically, consulting rooms have been a big desk in a 4x4m room with 1-2 client chairs facing the tenant. In a co-working space, you could accommodate 3-4 desks/tenants in the same area, especially if you're open plan. Generally speaking, you can charge 3-4 people for a desk more than you can charge a single user for a room.
More business than ever is online, and shared boardrooms suffice for meetings, private client calls, etc. Most people now get by without loads of filing and other storage space so a fairly standard desk (smaller than what we used 10-20 years ago) does the job.