The world was created with ten utterances. What does this come to teach us? Certainly, it could have been created with a single utterance. However, this is in order to make the wicked accountable for destroying a world that was created with ten utterances, and to reward the righteous for sustaining a world that was created with ten utterances.
The question is, the Mishnah first prefaces that the, seemingly, main reason why the world was created with ten statements is in order to "pay back" (or "make accountable" according to this translation) from the wicked who "destroy" the world that was made with ten statements, then, as if as an added reason, it says that it's also to give reward to the righteous.
Now, even though at first Hashem wanted to create the world with judgement, and only afterwards combined the attribute of mercy (as Rashi brings, to the beginning of Bereishis), but that was only before creation started, but the actual creation itself is built on mercy (and kindness).
So the obvious question is, why would the Mishnah start off by focusing on the punishment of the wicked, and only afterwards, as if to add some side reason for making the world in ten statements, that it's also to give reward to the righteous?
Shouldn't the main stress be that it's to give reward to the righteous, who sustain the world, except that in order to allow for free choice, keep people in check etc., there's also the idea of punishment/accountability?
Shouldn't the first thing mentioned stress the main point of creation?