Provided employee productivity is the same (or better) this model still has Zendesk ahead. It doesn't really matter if utilization is low - if you've closed 10% of your offices you're paying 10% less rent than you were before.

Would there be opportunities for further efficiency by fully closing them and renting space a few times a year? Possibly, yes. But that doesn't mean the current model isn't an improvement on the previous one.