I'd say it is good for people who just want to use Linux kernels and software for their systems, since x86 is still the platform of choice for that. Mature stuff, huge community and a lot of information available for free. Also when it comes to more complex communication stacks running on proprietary systems based on Linux, I think x86 has an edge.
Other than that, e.g. for RTOS operation, I think there's little reason to switch to x86 solutions, especially if you have to dig into assembler at times, for programming close to hardware, x86 is just ugly. ARM has way better solutions for such embedded systems and a much wider choice of processor cores.
I'd say that Intel's current success in IoT mainly comes from larger, more complex systems based on Linux and similar complex operating systems, like they are used in automotive, industrial etc. which are more of the Atom class type I think.
I guess it is for developers who are happier with x86 and there are quite a lot of embedded programmers like that.
The extremely rare application without a version for x86 likely has multiple better alternatives already available on x86.
The vast majority of useful software is available for x86 and more than likely x86 is the primary development platform that gets new versions sooner, better support than all other architectures, has the most users, and is the least buggy.
x86 is the lingua franca of general purpose computing.