It's part of Japanese culture. We use honorifics as an indication of our position in relation to the person we're addressing. I only just met you, so you are Psii-san.
[Of course, even with the strange typing and the whole psychic battery for a spaceship thing, she's not quite twigged that he might not know about Earth. When your home city is also home to a Dullahan, weird is relative]
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[Of course, even with the strange typing and the whole psychic battery for a spaceship thing, she's not quite twigged that he might not know about Earth. When your home city is also home to a Dullahan, weird is relative]