Current tagline - work from anywhere... It's too vague right
Likely best to setup some phone conversations with people here you find provide advice which seems to resonate with you.
USP may be useful + likely better will be to buy highly targeted traffic (to local area) + also use Meetup + other networking venues.
Search for my name + Meetup in Clarity + likely you can take what you find + generate a highly lucrative lead gen system.
Taglines that simply state benefits or features were in vogue at what point, but branding has evolved to more evocative taglines.
And, quite often taglines are benefit oriented not feature oriented. So, if your features are on demand, instant, and convenience, what is the benefit to your audience? Can you survey current customers, and find out what using your space enables?
Is it productivity and convenience? Or is is credibility? Or perhaps it's "no borders" because they can do business anywhere. It's impossible to come up with a good tagline based on a few lines--but listen to your customers, and you can start down the right path.
You may have answered your question. "On-demand, Instant and Convenient" could be your winning tag.
If I expect that a workspace provider will make it easy and convenient to work from anywhere, I'm questioning the "U" in your USPs!
Your tagline should make the client the hero of the story. So you could step into stories like "Be effective anywhere" without modifying your service.
But I'm thinking like a client. If I can choose between many workspace providers, I want the one where I feel at home instantly: that's what will make me productive, effective and happy. So I'd buy, "Work from home, everywhere" (or "Welcome home") - but only if you embed meeting my "homely" needs into your service, building up a profile of my tastes and preferences, thinking how the service can feel like arriving home when I step through the door and so on.