GoL is one very specific cellular automata. There was lots of work in the 80s and 90s on CA's investigating their properties, and some of them turn out to be much more interesting from an evolutionary-ish perspective than the GoL one. That could be useful if you were interested in evolving CAs.

Tierra was among the first documented examples of evolving code/evolving rules and led to many other ALife experiments with simple rules governing evolution yet complicated outcomes. The work done then didn't lead to any particular conclusions, but it could be inspirational when thinking about how to apply selection pressure, what degrees of freedom to allow, and the nature of the rules controlling the CA.

I wasn't name-dropping Tierra, I was giving it as one entry point (and an early one at that) into the prior work on this sort of thing. I could have left the name out, and then some other commenter (perhaps even you) would have said "oh yeah, why not actually give some examples?"