I think that's the big divide in templating languages— whether or not you trust the template author. Zero trust is a template like Liquid which has some trivial scripting stuff, but nothing non-halting (written originally for Shopify, where storefront owners could completely customize their look & feel).

And total trust is PHP.

In the middle is the whole realm of somewhat-trusted, where the templates can embed varying degrees of executable script, but you are at pains to let users know that too much embedding is a bad practice, and that especially if they're "just a designer", they should work with someone from software team to implement a properly-encapsulated solution for whatever it is they want to do.