Obs30 The ASIAIR app might just be a graphical interface (VNC or similar) to the actual processing unit on the RPi4/ASIAIR hardware. I think this is what StellarMate and INDIGO do, they „just“ offer an interface rather than using any native drivers on the iOS devices.
You are correct; although many "drivers" exist in the "server" (for example, a Raspberry Pi as server) too. Many things, like autoguiding cannot afford the latency to not be resident on the server. Others, like the planetarium component, will need to be on the controlling computer or tablet.
The main difference is that ASIAIR provides a turnkey solution (everything menu driven, so the 1,2,3 simpletons can understand), while StellarMate and INDIGO Sky (both of which can also run in a Raspberry Pi) both requires the user to have some intelligence to integrate a fully inter-operating system (guiding, image capture, etc, with components from different manufacturers).
It is just a matter of time before a group of enterprising souls will create such a turnkey integration using INDIGO Sky; that supports a limited number of cameras in a fixed menu, a limited number of mounts in a fixed menu, a limited number of filter wheels in a fixed menu, a limited number of focusers in a fixed menu, etc. (The reason I use INDIGO Sky as the example is because it truly supports macos.)
If this is created as an open system, others can fork the "product" to include their favorite cameras in the menu, or a decent electronic focuser, a better auto focusing algorithm, etc, etc.
Just like most people have stopped depending on a PoleMaster, I foresee the day when people will have better choices, where "simple" does not mean "crippled."
Chen
