The binary version comes directly from the binary given by the software provider, and it is patched by nix to ensure that the dependencies all end-up in /nix/store as usual packages. On the other hand, normal packages are compiled by nix directly from the source code of the package to obtain the binaries, and the binary obtained don’t need to be patched as nix’s compiler is creating binaries with dependencies appropriately located.
Each approach has their pro and cons (and I surely forgot some of them):
Pro of binary over source package:
- binary can come with more dependencies: usually nix does not pre-compile packages that need proprietary softwares. It could be an issue, for instance I think that blender does not come with CUDA enabled by default so you need the bin package to get cuda or compile it yourself.
- sometimes simpler to packages: sometimes it can be quite hard to build from source (election, java…) and packaging the binary directly may save some time
- quicker to build: since you skip the compilation, if your derivation is not in the nixos cache for some reasons it can save some time
- binaries provided by the software provider can potentially be more optimized (EDIT: subject to debate, see below): for instance Mozilla compiles firefox with some optimizations (PGO)
that depend the the typical use cases of users on firefox. If you don’t have the right compilation profile you can’t apply the same optimizations and you may end-up with a slower program.(not sure about this as NixOs finally added support for PGO)
Cons of binary over source package:
- less transparent: you need to trust that the binary sent by the company is obtained from the sources. Hard to detect proprietary blob
- it is not as flexible: from the source, you can choose precisely which compilation flag to enable, which revision of the source you need, you can test Pull Requests without waiting… you may also enable more optimizations options.
- building from source provides you a dev environment for free
- dealing with new architectures/cross compilation is certainly easier to enable in that setting since you don’t need to wait for the package provider to provide the appropriate architecture
- reproducibility: as pointed above nix is quite good to reproduce builds (can’t be guaranted however)
EDIT: sorry just saw your message tlater hope I’m not saying anything wrong ^^