My shul, and many shuls with which I'm familiar in the US, provide "Shabbat hospitality," meaning they will match visitors to meals and even a place to stay near the shul, if people are visiting from out of town. I see this thread as the same idea.
My family and I could go out to a Shabbat dinner at one of the hotels in Jerusalem, but to my mind, I would rather we have the experience of seeing how others enjoy their Shabbos, and meeting some kind and interesting people. Anyone who opens up their home and their Shabbat table is epitomizing Avraham avinu and the midda of hachansat orchim. That's the kind of person in whose home and at whose table I would like to be welcomed.