At least with AGPL software, if this happens, it will force those competitors to release their secret sauce, too. Those competitors will have to open source all of their changes, meanwhile as the copyright holder, you're able to release proprietary modules or changes at any time, and those competitors are out of luck if they want to use them. Should they attempt to compete on feature parity, their additions will need to open source.
In this case, we are talking about client side software. It runs locally on the device. This means that the distinction between the GPL and the AGPL is not really relevant. And any competitor preparing modified binaries would also need to release their source.
