there has been a ton of work on making comptime a pure and deterministic execution environment. I do not expect that work to stop. I don't know where you are getting the idea that it is not an important design consideration for the language.

to expand, if two different host platforms cross compiling to the same target platform have different results, I am almost certain that would be considered a compiler bug.

if you're pointing out that a runtime operation and a compile time operation might not agree, I'd be more interested in understanding when that would ever have any meaningful impact on anything. given the compilation is supposed to be deterministic, the difference can easily be addressed by comptime branching on target architecture in the rare case that it matters for your program.