We've already seen the Marketplace and even Junes, with Rikku before. Yes, we'd meet Yosuke, but we can't befriend everyone in the world and we have only a limited time before the sidequest. Ignoring the main plot (Odessa) and the sidequest (Jax, potentially Nook, the Anthro Park) to go making friends with someone just because we have a Level 1 Social Link with their girlfriend seems like a dumb move to me. We're not going to be in Sector 7 forever and we almost certainly won't be bringing these all our Social Links with us.
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Some things are more important.