After the 1st JIT-compilation (which here we treat as C++ static compilation), there is no compilation cost. As long as you avoid doing dynamic things (e.g. GC), there's a great case to be made for real time Julia.
Of course, but other than in C++ you need to use ways and means to achieve this - never hitting u compiled code - that are not very natural to Julia. Yes it may be possible to compile Julia code to binaries, but it obviously is neither straightforward nor widely used.