"I must hide my cheat power..."
15 seconds later
"let's go in this very hard dungeon where i won't be able to hide my levels or my cheat!"
This one is a little bit better...
If I recall correctly, in WN version, her little sister is literally Sakura in Naruto childhood.
She knew she is just a deadweight but she still choose to tag along or run after his brother, because "I want to help you" luke any damsel in distress.
And to be honest I believe a lot of WN reader want MC to just use her as monster bait to fulfill that wish