Doesn’t that imply an interface is necessary though, so you can compile (and potentially release) the components separately? I don’t use .net but this sounds quite similar to pulling things into separate crates in Rust or different compilation units in C, which is frequently good practice.
Definitely that could imply the necessity of an interface, but often it's simply done, because everyone working in a project blindly follows an already established poor convention.
by "it's common in the .Net world" I mean that it seems to be an antipattern that's blindly followed. If there's only ever one implementation, it is the interface, imo
