If you're creating a real dedicated space then that can be justified. If it's to the point where you have to buy a new house/apartment with an extra room then I'd rather just have a real office space instead, especially as an employer.

Imagine if you will: a condo building that's designed as a mixed residential/commercial space, where there are apartment units, and office units that are free-to-use for anyone with an apartment there. And the office units are pre-furnished.

Now you're essentially paying for a co-working space (whether you use it or not or whether there's always a space available) through some combination of higher unit prices and condo fees.

Wouldn't it make more sense for those who need/want a work area outside their apartment to get a co-working space?

The idea here isn't that you want a work area outside your apartment. The idea is that you'd ideally want an extra room in your apartment to serve as a home office, but you are willing to time-share it with other people to make it cheaper than the cost of an actual additional room for your exclusive use. But you still get to wander over there in your house slippers, just like a dorm kitchen.

Sounds great, but the cost of that office square footage is going to be reflected in the price of the residential units.