What's the goal? Saving electricity? You can get very low power x86 boards that'll be a lot more compatible with everything and also a lot cheaper than this. It's easily doable to buy a power-saving computer that can tackle everything software except games and high level graphics stuff for less than $80.
I would not consider ARM to be safer as x86 regarding vulnerabilities or hardware backdoors. Both current generations of CPUs are just too complex to make a blanket statement like that.
ARM also doesn't scale well in practice price-wise. It's cheaper to get a few older x86 than many expensive ARM SBCs and the older x86 together will still have vastly more performance.
ARM is good for mobile computers (smartphones and such) because of the high energy efficiency and every bit of performance leveraged by the custom OSes (android, ios) written for that usage. ARM would also be good for low end workstations where you could save a lot of power, the problem is just that the Linux landscape of software was just not written with these CPUs in mind. Especially support for inbuilt graphics is very, very poor.
I have an A20 Cubietruck board and it has (slow) SATA and decent ethernet. The A20 is an older dual-core ARM SoC and is pretty well supported in Linux mainline. There's even a project with which you can leverage the decoding of h264 video in it's hardware, and other hardware bits and pieces like AES acceleration are leveraged by the kernel too. It's CPUs are also not susceptible to Spectre. The downside is that it's fairly slow. It's *almost* enough for being my comfy linux workstation, just the (lack of) support for Mali graphics has stopped that so far. I need to check out the opensource Lima drivers, maybe they're usable.