What you're missing is that, unlike any other commonly used language runtime, compilation in CL is not all-or-nothing, nor is it left solely to the runtime to decide which to use. A CL program can very well have a mix of interpreted functions and compiled functions, and use late or eager binding based on that. This is mostly up to the programmer to decide, by using declarations to control how, when, and if compilation should happen.
It should also be noted that by spec symbols in the system package (like + and such) should not be redefined. This offers “unspecified” behavior and lets the system make optimizations out of the box.
Outside of that you can selectively optimize definitions to empower the system to make better decisions at the cost of runtime protection or dynamism. However these are all compiler specific.
To be fair, any dynamic language with a JIT will mix interpreted and compiled functions, and will probably claim as a strength not leaving to the programmer the problem of which to compile.
