This intersects with a raging debate in Origins of Life research. The Miller-Urey experiment demonstrated the production of amino acids from simple gasses thought the be present in the early Earth atmosphere and energy.
The problem is that you can add amino acids into a flask, stir, and not much will happen. You can pump in all the energy you want and all you'll get it tar. Before you can even start to make proteins, which is what makes life, you need enzymes. The trouble with enzymes is that they're, well, proteins.
So how do you get the proteins that make proteins in the first place?
One line of investigation says that you don't. What happens instead are stepping-stone chemical processes that turn energy from the environment into self-reinforcing cycles that build complex molecules. Over time chemical evolution takes place to produce self-reinforcing systems that make something that's very close to amino acids and/or proteins. We don't know what these processes are, but we can deduce their necessity given the above conundrum. Chemical evolution is a process we observe on the macro scale when, for example, viruses evade vaccine defenses.
In other words, finding amino acids just says that the processes that produce amino acids are ubiquitous. This is hardly surprising given the molecular simplicity at play. There's just a handful of atoms and they pop together following well-understood rules. The paths to making amino acids from simpler inputs is short, well-defined, and not entropically disfavored. It can (and does) occur abiotically.
Finding enzymes or other complex proteins above statistical background levels on the other hand would be different. That would be a world-changing find because it would be strong evidence of previous life. Even more, you'd be hard-pressed to find any other explanation.
But it's not just proteins. Any sufficiently complex molecule found above expected statistical levels due to random reactions would be strong evidence supporting previous life.
As an aside, finding enantiomerically-enriched amino acids would also be an important finding for similar reasons. The article doesn't discuss this, though.
For a high-level overview of what all of this about, check out Lex Fiedman's interview with Lee Cronin: