In order to answer this, I have to approach this from a few different perspectives.
First, we have to look at the context of that sentence in the OP-
Instead, I think it's much more interesting to look at what the difference is when you look at games that are d6 only, and games that are d20 (the D&D set or subsets thereof). What are some of the cultural assumptions and baggage that go into deciding one or the other?
Then contrast that with the concluding statement-
On the one hand, I don't want to put too much into this- there are long-standing commercial games that have used the d6 mechanic, from GURPS to WEG's D6 system. It is also entirely possible to go to itch.io and find indie games that use d20.
So on this level of generality, I'm not saying that every single game has every single cultural signifier! In fact, as I will (eventually) further develop, and I mentioned in the prior response above this, I often think that the choice of a given resolution system in terms of the dice chosen isn't necessarily a reflection of what is the best fit for a game- instead, you end up with choices like, "This is an indie game, and not a commercial D&D-like game, so it will use d6," as opposed to genuine thought as to what dice make up the best possible experience for a given game.
But to delve more deeply into this, I would say that we can look at an example of a game like Lord of the Dice
(the thought experiment / parody by Costikyan/Goldberg from 1979)- however, simply change and simplify; replace all dice mechanics with flipping a coin. Replace success and failure with "Yes, and," and "No, but ..." Add in some type of meta-currency for players to spend to move results from "No, but ..." to, "Yes, and," and provide a thick set of guidelines that constrain how players can declare actions and how GMs can adjudicate results - in other words, move the heuristics for the fiction from the shared consent of the people playing to written guidelines.
I realize that was a big paragraph with lots of thoughts, but I want you to think about it for a little while and try to imagine that resulting game using a coin flip as the sold method of randomization in a game that was otherwise heavily narrative. Now, call the coin a d2. During the game, a person might say that a given "roll" (coin flip) mattered a great deal! The player might be out of their metacurrency, and a bad roll on the d2 might mean the GM gets to use a specified "No, but," against them that will SUCK. Conversely, they really want to be able to ,"Yes, and!" This is super important for them, the narrative, and the character!
But in terms of looking at dice rolls qua
dice rolls, the actual rolls matter less. Maybe you think this is a distinction without a difference; but generally
, it is my opinion that in terms of cultural signifiers
, when I see a d6 based game, I assume that the creators are more concerned with features of the game other than the die rolls.