The Halls are a typical family who don't know that they're in a science fiction story. Mr. Hall drinks and Mrs. Hall nags him about drinking. Mr. Hall isn't so quick (he has a "heavy intelligence" and Mrs. Hall takes out her frustrations on Millie, the serving girl .. In other words, they are a stereotypical country couple found in many a novel (and in real life, if you know where to look.)
This is why we like them in The Invisible Man: they're totally normal folk who are put into a situation that is totally abnormal. We may not identify with (or even like) the Halls, but the fact that we recognize them as "normal," helps us understand the shock of the abnormal stranger. This is probably the role of every character in Iping, actually. They are normal (though very countrified), which makes the book seem more realistic. Even if we don't identify with them, the fact that they're realistic sets up a stark contrast to the Invisible Man.