So in theory Julia can solve the two language problem but in practice, there are well optimized tools like openblas and torch that is highly optimized, so we simplyuse them as they r faster.
Flux.jl seemed so promising a couple of years ago but has definitely lost its lustre (my friend who had been using Julia moved to Pytorch) . I tried Knet.jl but i found it impossible to comprehend even for simple cases.
I thought Julia would be great for NN but turns out that is not true as of today. I tried some NN in Julia and Pytorch and the pytorch version was faster. CPU and GPU. So i am moving to Pytorch too.