A full programming language is the natural choice for people who are full programmers. But for people who aren't, they're intimidating and add a lot of complexity. Templating systems are much more approachable for people who have a lot of experience configuring things via big blobs of text.
As a programmer, I would personally rather express everything in a programming language, so I get your perspective here. But it isn't an accident that there are so many ops-focused systems that are different takes on just automating the things people were previously doing manually.