In practice, it means that unlike most native-compiled languages, if you want a data-oriented approach without having to worry about system details at all, you can do that. Your program will still be strongly typed, but you're not obligated to worry about allocation, reference vs value semantics, ownership, or initialization details. For programs that shouldn't have to worry about those details, the Nim team has done a lot of work to make sure the language gets out of the way and lets you process data. Then, you get a fast binary comparable to the results you'd get from C++ (with a lot more effort).

In buzzword-speak, it's easy to write programs composed of nearly pure business logic while getting C++-level performance.