In my opinion there's a "level 4.5" in between structured templating and full-blown procedural scripting: Using a general-purpose language to generate structured data, but then handing that over to a simpler system to materialise.

Pulumi is the best known example. Also, any time a normal programming language is used to generate something like an ARM template or any other kind of declarative deployment file.

This is the best-of-all-worlds in my opinion: Full capability, but with the safety of having an output that can be reviewed, committed to source control, diff-ed, etc...