There is no notion of ground term in Life. In Life, two things are equal only if they have been unified together.
All logic languages have to name the data objects they handle.
Using variables is a compact and meaningful way to do this. Variables in Life behave in the same way as variables in other logic languages such as Prolog. The order affects only the execution efficiency. For example, integers. One cannot, except in a roundabout way as a sequence of unifications that must be executed.