Hardcore proponents of this style often incant 'DRY' and talk about reuse, but in most cases, this reuse seems to be much more made available in principle than found useful in practice.

There's also the "it makes testing easier because you can just swap in another interface and you don't need mocks" argument - sure but half of the stuff I find like this doesn't even have tests and you still tend to need mocks for a whole bunch of other cases anyway.