"In my name, I command all living beings within the Solar System to witness these events," is actually a more literary version of the statement. In real life, no normal Earthling would speak like Ma Ran just did.
However…
If the same content were transformed into a more down-to-earth version, it would become "I'm going live now, everyone still alive in the Solar System, come be the audience!"
Hmm...
The persona of someone with a strong vanity, who loves to show off in front of others, still needs to be maintained.
Taking this opportunity to perform is not out of the question.
After all, the ability to play is Ma Ran's bread-and-butter skill.
He couldn't possibly put it aside and let it gather dust.
If he performs well, who knows, he might even gain feedback from the ability to play, further enhancing his own foundation!
