Final answer:
Erin Kelly includes the text message alert detail to provide insights into Kaori's character, possibly reflecting her personality or interests. This detail also indicates the modern setting of the novel, while suggesting advanced technology skills is unlikely.
Step-by-step explanation:
The reason Erin Kelly might include the detail that Kaori's text message alert is the sound of bells ringing at a Buddhist Monastery in her novel Hello, Universe is primarily to give insights into Kaori's character.
This choice of a message alert could suggest that Kaori has a connection to Buddhist traditions, an interest in spirituality, or a calm and grounded personality.
Additionally, it might also convey that the novel is set in modern times due to the presence of technology like text messaging.
However, it's unlikely the detail is meant to indicate Kaori has advanced technology skills; such a conclusion wouldn't be directly supported by the specific nature of the ringtone.