Yes, you need that datastore connected to any hosts that can consume those items, because a CL is backed by a datastore. It's really just a metadata layer/wrapper around a datastore folder. What I try and do is create a "utility" datastore and mount that to all hosts. That datastore isn't for anything other than content--whether that's backed by a CL or not. One of the reasons why that's actually helpful is because with vSphere templates, your hosts have direct access to those blocks over their storage fabric. If that weren't the case, those bits would have to be pushed across your Ethernet network through the management vmkernel interface to the destination host. Definitely much slower clone/deploy times in those cases.