Unlike traditional phone companies (such as Bell), most Voice-Over-IP phone service providers (including ItalkBB) cannot accurately locate the phone user's exact location/address. This is probably due to current technology restrictions, which could change in the future.
In case of an emergency, the 911 operator would not be able to pinpoint the exact location/address immediately. The caller would have to tell the 911 operator that information before they can respond to the situation. In some cases, this is not possible (for example, senior parents who cannot speak English/French, or someone is too sick to talk, etc). On the other hand, with Bell, the 911 operator immediately knows where the caller is. If the caller is not talking, they will still send the poilice, actually even quicker, fearing the caller is in real danger.
That's why using the VOIP phone service as your local phone service does carry some risk in case of an emergency when 911 service is required.