X Card and other resources in the toolbox come with rules, whereas when groups I had once played with "direct communication", that's what happened when the content of the game triggered the interaction is that the conversation has sometimes completely failed to improve safety and sometimes aggravated the situation.
Just to quote the rule, according to the John Stavropoulos X Card documentation, when you
"Lift this card or just tap it, you do not have to explain why, no matter why."
This created an expectation in two of my gaming groups: by agreeing to use the X Card, this concept was introduced and applied by a conscientious, cooperative and responsive group.
On the other hand, the simple fact of relying on "simple communication" encouraged people to … wait … to communicate. As in, be free to bring what they want to the conversation. This included questioning the triggered person and unedited reactions, which had just created additional triggers and the badness of uninformed judgments. Not too safe. By do not do anything proactive to actively promote a safe space, some people were absolutely not prepared to show empathy and attention when a triggered person requested accommodation, which resulted in not give her what she needed and asked, because of lack of understanding or disagreement.
Now, I imagine (I'm only saying rhetorically. I did not try that.) It's certainly possible to have a conversation before the game starts on the fact that the way you are going to ensure security is to do something very similar to what the X Card protocol describes, but, now, you are no longer in the territory of "simple communication".
Given my personal experience with the two options presented in the question, X Card or nothing special, the main benefit is the X Card. comes with trainingthe more he ensures that everyone is on the same page before the game starts, to the extent that willingness to participate in a safe space at all go.