@theilikepie: Hey why dont you leave the convenience of modern life to live in a medival style world where you can die any minute?
A world without toilette paper and where convienient life magic like "clean yourself" is a lie. Change to a world, where a dragon can chew you up, from a world, where you can be assaulted on the street by a stray cat! Want a hot bath? Go find yourself wood or let your convenient slave do it.
But then again, magic instead of medicine. Not sure what wins out, but "resurrection" is a strong hint.
@Yamibi: Why dont you live in modern world when you are nothing than a mear jobless uneducated woman, there is always a rat race, you can't find a decent husband, have no family at all (all dead), government doesn't at all care about you coz your existance is insagnificant ? But well you have internet so its much better than the world where:
You are appriciated, will be provided for as a sister of a hero who saves the kingdom, already have decent husband material, and people who care about you.
This is a tough choice indeed. There are corrupt nobles, but saving the world and the royal family being in debt to your family and in friendly terms with you might work like a charm. But no video games, internet and mangadex for you! Tough indeed.
The best worldly reason to stay in a "other world", having super awesome cheat abilities (or at least one) is missing for big Sis and lil'sis's cleansing power might not be useful later on. They rely on the King's well meaning, but in the end he is a dictator and could just change his mind after a few years. They would totally rely on the conections they formed, but they
do have those connections, that give them the edge in this world. On their earth they would be alone again, but not in such a high danger of being messed with.