I want to rename the theme. Why is it not a good idea?

Please note, that if you want to rename a theme - that's not a good idea. 

Such steps may break a theme or lead to unexpected issues. 

Each theme contains its unique IDs, classes, and code which are connected directly with a theme's name. 

The renaming may break these connections and you will lose a theme's functionality and correct appearance + you'll miss the future product updates.