A touchdown space is a short-stay workpoint used for an hour or less: a bench between meetings, a laptop bar near reception, a perch for a visiting colleague. They are usually unbookable by design, absorbing the overflow that would otherwise consume desks.
Touchdown spaces earn their floor area by protecting bookable desks for people doing a full day. If your all-day desks keep getting used for forty-minute stops, you likely need more of them.