I totally agree with you. And have some more thoughts why all this what GrandCentral and Gizmo do is no big news to me and we can all do this at home:

If we all would be using ENUM the deal between GrandCentral and Gizmo wouldn’t be big news. With ENUM I can already route my PSTN number to my Gizmo account. VoIP users that call this number and do an ENUM lookup can call me for free.

Why bother for another number from GrandCentral?

I can implement the same call routing features of GrandCentryl in my analog telephone adapter (ATA). I actually do. So whenever somebody calls my years old PSTN number I can let it ring wherever I want (for instance on my Gizmo Project soft phone or my mobile phone) and I can also filter the callers like GrandCentral offers.

Why pay extra for a service which I can already use at no extra cost at home?

Well, some say that ENUM is difficult or that they just don't know it.

But the point is that it’s totally easy to do an ENUM lookup before every call. SNOM VoIP phones do it automatically before they start the call. The VoIP providers could do it automatically before the VoIP call starts. Also they could enlist all their numbers in ENUM. The client wouldn’t even notice that ENUM is working in the background. It would just be all over IP and for free. But the VoIP providers don’t do it because the earn very well not doing ENUM and charge for calls that technically could be for free.

Others say that we should at least give GrandCentral credit for is their rules processing.

Well, the newest versions of the Fritz!Box do this out of the box. No complicated acronyms needed for installation. Just some clicks in the browser.

Incoming calls can be treated individually. You can for instance block unwanted calls or pass them to an answering machine. Friends and business partners can be redirected to a mobile phone, even if the call signal of the phone that’s connected to the Fritz!Box is switched off.

I am using such a Fritz!Box at home. It’s connected between my old telephone and the DSL connection. So all my calls go for free or for very modest prices over the internet. I do the configuration in my browser and it’s very easy. You can see an example here.

In fact the Fritz!Box is an entire PBX and cost me only 30 Euros, because I bought it used. It can do everything that GrandCentral does. Even an ENUM lookup before every call. But this is a hidden function for which you have to tweak the Linux that runs on the box. The Fritz!Box is getting better and better with every firmware update.

So to me GrandCentral is no big news and no necessary service.