The most common question I encounter about ARKs is, what are they used for? The FAQ doesn't address this or the more general question of why there would exist the various other identifier schemes that are referenced. (At the end, the discussion of ORCIDs and UUIDs addresses purpose more clearly--I think that we need to address the purpose and applications of ARKs with equal clarity.)
In the question 'How do ARKs differ...", I'm not clear about what "non-siloed" means exactly. Also, particularly in light of the Sustainability FAQ's several questions about costs of ARK services and the existence of paid services such as EZID, is it appropriate to refer to ARKs as being "non-paywalled." Clearly use of ARKs is not "free" for users of services like EZID, and use of ARKs may not be free for many users in the future. If you mean something different from "free of cost" then I think that has to be made explicit. I generally think of a "paywall" as a vendor's mechanism for managing access to paid subscribers; can't ARKs also be potentially used for resources that are commercially access restricted?
I wonder, too, whether it might be useful to note that identifiers refer only to resource location without implying anything about the attributes of whatever item might reside at an address; in other word, perhaps work in a sentence or phrase that simply notes that content represented by a persistent identifier is subject to "content shift"?
