It does however also challenge a number of preconceived ideas about mobile phone service. Perhaps foremost among these is that you don't have to have a mobile phone number on a mobile phone. It is perfectly possible to have a mobile phone that can make and receive calls and send and reply to SMS with a geographic number (01/02) and also certain other types of numbers. The upshot of doing this is the caller to the mobile gets charged as if dialling a landline. However the mobile phone user will get charged maybe 2p per minute to receive the call. Now that might sound strange and counter-intuitive but it is the way mobile phones have worked in the USA for years. The question remains as to how willing the UK market would be to accept this change. It could make perfect sense. Think of a sole trader who might find potential clients more eager to call because they are dialling a "landline" number. Would such a user be happy to pay 2p per minute for such a service? However about businesses who pay say 7p per minute for calling their employees' mobile who could reduce the cost to 3p per minute total.
Having your own voice service on a SIM also allows services such a voice and SMS recording and archiving to be offered. This is a hot topic in a number of industries. You could have group calling, unifed voicemail on your landline and mobile. IVR and time based routing. All services which the current mobile operators don't offer.
So would you take up such a service and enjoy the benefits of a geographic number on a mobile phone?