Calling Controller (App.php) functions from setup.php (and other controllers)

I thought template() at first as well (function inside helpers.php), but am using Template() in my production code with previous Sage versions and it’s working as expected. I found that here on discourse some time ago, but here used to output shortcodes as @MWDelaney shows: https://discourse.roots.io/u/MWDelaney): Shortcodes that use Blade templates and get Controller data. I do admit I don’t know where this functions comes from.

It helps when outputting template code from Ajax or when you want a function that you can use that outputs the whole view based on controller info.

Does that make any sense or am I abusing certain paradigm?