It would be very helpful to be able to copy all collapsed rows when a main row is selected for copying. At present it seems you have to expand all collapsed rows in order to cop and paste them.
I group items at multiple levels into sections which are collapsed and sometimes would like to make a copy of the entire section. Having to expand collapsed rows each time can be very frustrating.
See the Tip (in a green box) at the bottom of the linked article below. It has a helpful suggestion regarding this situation. https://help.smartsheet.com/articles/2482601-copy-paste-basics
Hope this helps!