It probably wouldn't be useful for folks who are dumping their POTS line but for those who would like to send local calls to their standard ATT / Verizon / Etc "line" it might be useful to have the ability to upload Npa / Nxx lists to the Obi for it to search. The ability to specify a particular Area Code is a start, but many area codes contain lots of Nxx [prefixes] that are not local.
I've been thinking some of what people may be asking are a bit much for our little box, and hence "one more piece of hardware", but Obihai could start putting hooks into their code and leveraging more capable hardware for those needing it.