Because their bosses dream up scenarios where customers will be generating config files to be used as templates, etc..., and they're just trying to solve whatev

Because their bosses dream up scenarios where customers will be generating config files to be used as templates, etc..., and they're just trying to solve whatever problem was put in front of them and "we'll use YAML", IME. Of course, those scenarios never play out, the thing is bastardized, some new responsibility gets created for some new role where it's their job to handle the template generation on a per customer / per site basis, and on and on we go.