In simple terms,the phone is the one that sees the provider's network (frequency), It uses the SIM card to identify the frequency on which to make a connection to, Authenticate and authorize the user to gain access to that network's resources e.g making call.
A normal laptop ,the WIFI hardware was designed to see on networks operating on the 2.4Ghz- 5Ghz frequency band, but the Econets and Telecels use GSM/HSDPA which operate on 850-1900Mhz/850-2100Mhz respectively. Hence you wont see these types of networks on the Laptop. The hardware is incompatible.
That is why you wold need 3G dongle & a SIM card to connect to such networks.