The security industry is a very large industry, there are all kinds of different avenues and jobs that you can take. Satellite use is not exclusive to this industry specifically, and it is only used in security jobs where there is no opportunity to use standard communication.
We’re not talking about your standard satellite that A1 Digital would install, we’re talking about satellite phones that have access to communication as long as there are functioning satellites in the sky. Satellite is the only form of communication with a worldwide distance at sea, radio-waves won’t travel too far and there are no masts out in the sea that will enhance signal, so satellite can be used for not only telecommunication, but also internet access. You might need a bigger receiver for internet access though.
It’s not just maritime security that will use satellite phones, some contract security stationed in underdeveloped countries will also be using satellite phones to contact their superiors and get orders. Satellite is the most effective communication tool under these circumstances, and unless something better comes out, it’s going to be used for a long time.