Relative to the side-channel attacks on Intel CPUs, I don’t really see the issue here.
The general prerequisite for these attacks is a hostile application executing concurrently on the same CPU (usually, on the same core) as the application whose data you’re trying to steal.
This is a potentially huge issue in the DataCenter, where multiple users’ applications are running on the same CPU. But, if we’re talking about ARM chips in a smart phone or an SBC in your home, if a hostile application is running on your device, then you have probably already lost the battle.
OTOH, as a proof of principle, I think this is important. Up till now, Intel has gotten all of the bad press about these side-channel attacks. But they’re really a general feature of modern CPUs and the tricks designers have used to try to extract better performance from more-or-less the same hardware.