First of all considering this is India and the current telecom mahabharat in the nation their rates are very reasonable. The idea of not selling the SIM alone is that since now they provide only data service they want to earn more profits by selling the devices rather than just selling the SIM. Would you pay them 1000 bucks only for the SIM??? If they had sold only the SIM the market would have flooded with chinese 4g dongles and they would not benefit much from it. They would then have to depend on customer staying with them for a longer time. When they sell the device the customer automatically gets tied up in a relatively longer duration commitment than else wise....An interesting point, ipads don't have voice either but still work with sims for data. So the no voice argument for lack of sims argument does not fly with me.
That airtel is doing this means the dongle is a waste and is only good for airtels network. If they are going to lock it like this i'd expect the price to be a lot lower 50% of an open dongle. Its a multi-mode dongle which means it automatically switches between 2/3 or 4G. But no sim is a downer. Prevents the user from choosing his own open dongle and pairing it with a router of his choice.
And go ask Airtel for a SIM for your IPAD see what they can answer.... Honestly I have not tried that. Again TBH I quite agree with their current strategy about selling 4G connections with locked devices and not sell only SIMS.
Things will be better and open when slowly they will start expanding their 4G services to many other cities and might start Voice + Data also.
(Off topic): AFAIK the Airtel guy who gave me this info said that there is some stupid TRAI and Govt laws ambiguity due to which they cant start Voice call service on 4G yet and it will be worked out soon. But again nothing official on it.
Also in the 20odd min I spent in their booth trying the device I found atleast 4-5 foreigners who were ready to pay 4K per month for even 10GB of data. And additional charges per GB. The only reason being they wanted good speeds when they work from their hotel/apartments. So there is certainly a consumer group for 4G even now.