AOT compiling was initially all about iOS (where JIT isn't allowed), but you can now do that everywhere with "application snapshots" which were recently added with Dart 1.21.
Unlike the script snapshots, application snapshots also include CPU-specific native code in addition to the serialized token stream of the source code.
So, you don't just skip the parsing stage, you also skip the warmup phase. Your application starts instantly and it runs at full speed from the get-go.
I think it's a work in progress, but main benefit at least at the time was faster startup.