I head over to the co-working location for the commotion and activity honestly. Everyone is still working and so it's not like a social event but I need to be around other humans while at work from time to time.
Plus, one time I met these kids (likely right out of college) working on a IOT weather station. They had a few customers and we're working on their hardware at Common Desk. I chatted with them and gave them some biz pointers and some contacts from my network. I got a real kick out of that.
If you're just working from home for another job though, there's not as much of a social aspect since everybody is just...working. I get much of the same benefit by going to work in my local library (out of the house, working around other people who are quiet).
But I think that, for me, a social app wouldn't be able to replace a physical work space. It's not just the interaction with co-workers, but also the separation of work and home. The routine of riding my bike to and from the office is like a mental barrier, helping me to switch between work and leisure.
By going to my office, I effectively switch to work mode. I'm less inclined to get distracted (HN, YT, Reddit, etc) while I'm at the office. Then, during the ride back home I have time to reflect on the day. By the time I'm back home my mind is clear and I can relax.
My findings are that (at least in the Netherlands) there is plenty of opportunity for new co-working spaces. Currently it's hard for small or solo businesses to find a suitable office. All offices I found are either geared towards larger groups (10+), or had ridiculous requirements to be eligible. All the 'innovation' spaces are hard to get in when you just make a software product. They require some 'impactful' business to be accepted, which basically means you can choose between creating yet another replacement for plastic straws, or blockchain.
I don't need foosball tables, I don't need eco-vegan food, I don't want to attend blockchain disruption events. I just want a desk to sit at, and do my work.