I recognize the point of the blog post, but I think that's it's more dismissive of interfaces than is warranted - the title outright says to mostly stop using them, and the 3rd paragraph suggests their use is split between over-engineering and mocking. It's not until the end that you start talking about what else interfaces are good for, and even then there's a sense that you think they should be used with care.

I just disagree with that; I think it's far better to have an interface you don't really need lying around than to be caught without one when you do need it.