@bonnielu You may not value appearance and that's the only value any fashion item that most of us ever buy can offer. However, if one of the bags your sister gives you appeals, I know for me that would be easier to use that than jumbling my things into a shopping bag.
For any bag you do not expect to use, donate your gifts to a local shop you feel can benefit. (You're not obligated to tell anyone. They're yours and it's just fine if you and your sister value different things. Thrift is where my older leather bags have gone, but I should tell that I have also donated a number of Sac bags just because the ones I had made finding what I wanted irritating! I prefer the structure and organization of a bag.