I see for JuliaCall:
SystemRequirements Julia >= 0.6.0, RCall.jl
So I assume RCall.jl is used. I’m not sure but I think it allows calling R in the same process. R is GPL, so that means your whole program is GPL. If you’re trying to get out of that, then Rcpp doesn’t help you either. So what’s the point of (small) binaries for you? [It’s already a problem to distribute GPL-free R-only binaries and/or small R binaries, seem to be 77 MB+.]
In some few cases (small) binaries can help, but in very many cases distributing source code is ok (and/or sysimage), and startup as fast. And the source code can be way smaller than the binary…
That doesn’t seem like a problem. You would do same as with Python, you distribute the (likely smaller) source code, and let the package depend on julia (rather large but one-time shared cost) runtime (apt or snap or whatever) package…
Again not a problem (e.g. do most Python users compile in that setting?). It seems like a lot of the fixed overhead (of the runtime and LLVM) could be shared across containers? Startup speed doesn’t need to be large, even with source code (assuming precompiled), getting better in 1.9, or if you can compile your source code (partially or fully) to a sysimage.