Being an introductory chapter, it introduces the characters and establishes the family dynamic. The personalities are so well characterized that it is worth it with small gestures to see who has influenced another. George is passive aggressive and crushes those he sees as inferior, as does his mother. Rudolf and Kyrie are calculatedly presented as a patriarchal couple, with the seductive man tied up by a woman much more efficient and intelligent than him, but who respects his pride and shuts up to let him show off - which, above all, we will see later. -… You have an idea.
Of course, the western world is also being introduced to us as a contrast to Higurashi, who could not be more Japanese. It may seem like a superficial detail, but I think the whole western naming thing is a good way for Ryukishi07 to connect Kinzo with Bice. We know that his fascination with the western is very old, perhaps a form of escapism, and that before being assigned to Rokkenjima he baptized his children with foreign names. So when he met Bice an immediate bond was made. After all, she was not only a very attractive maiden in distress, but an exotic foreigner who adapted to her tastes for anything that was not national.
That all the grandchildren maintain this custom, on the other hand, speaks of the struggle of the brothers to make their offspring pleasing to Kinzo's eyes. After all, if Jessica is not acceptable for being a woman, George seems very soft in Kinzo's eyes, Battler rejected the family and Maria is not only another woman, but a girl that Kinzo disgusts ... Anyone could have an opportunity. (Important: this is not correct, as, as noted in a comment, it was Kinzo who chose all the names except Maria.)
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In the manga, practically this entire chapter is skipped and uses a more simplified presentation of the characters, directly on the ship that is heading to Rokkenjima. I think the story does Battler a disservice by showing him right off the bat screaming and suffering, and it doesn't portray his cousins very well either (except maybe Maria). In George's case, all his passive aggressiveness disappears. I wonder if it was a conscious decision by Ryukishi07… Unfortunately, Maria's reaction to the absence of the temple is over-emphasized. In the novel he keeps repeating the same thing, but he doesn't have that extremely sinister aura around him. Everything is much more artificial than you might expect from characters like Umineko's (Battler gets to touch Jessica's chest) and, although understandable due to the lack of space, this means that even more characters will have to be introduced at once.
