From ember-template-lint documentation (https://github.com/ember-template-lint/ember-template-lint/blob/master/docs/rule/no-unbound.md):
```
{{unbound}} is a legacy hold over from the days in which Ember's template engine was less performant. Its use today is vestigial, and it no longer offers performance benefits.
It is also a poor practice to use it for rendering only the initial value of a property that may later change.
```
Co-Authored-By: Jarek Radosz <jradosz@gmail.com>
