SIM cards are used for authentication on the network. Using a dedicated encryption chip is this only way to ensure authentication, software keys are too easy to steal.
Today, any device with a sim card reader and GSM antenna may be used as a phone: computers, tablets, and so on. I don't know where you live, but, in many country, today, you can buy phone service without a phone, and with no lock-in period.
If the aim is to reduce cost, is it wise to split the drone and the camera ? In a comment to this one, the DIY drone is around 250$, the GoPro itself is 200$, the Bebop drone (whose camera actually use the same sensor than a GoPro) includes drone and camera (allowing to use flight information to improve video, and video to improve flight control), cost does not seem to be the right reason to make DIY drone. Technical interest may be relevant, as well as specific requirements, but cost is rarely a benefit from DIY.
My comment isn't neutral, as I work at Parrot, but I think it is honest. I also make my comparison with an expected price of 500$ for the Bebop drone, but I have truly no idea of what the actual price will be.
Why was this link put into hacker news ? It's old, it is also based on inaccurate understanding of git. Experienced git users don't need this(1). Is Hacker news designed to publish hints for beginners ?
Hacker news aimed at links that are deeply interesting.
> "A crap link is one that's only superficially interesting. Stories on HN don't have to be about hacking, because good hackers aren't only interested in hacking, but they do have to be deeply interesting."
In my opinion, this link is superficial, and does not go in the real topic : the workflow.
(1) In my opinion, an experienced git user should know what he need to fetch, and when he should have a merge instead of rebasing some commits, and should also know the commands to do so. It's more a matter of workflow than a matter of git command.
Today, any device with a sim card reader and GSM antenna may be used as a phone: computers, tablets, and so on. I don't know where you live, but, in many country, today, you can buy phone service without a phone, and with no lock-in period.