Find Replace dialog box to allow access to document for copy paste
When you open the find/replace dialog box you no longer have access to the document so you can copy text. So you have to copy text -> open find/replace box -> paste in find field and click done -> copy the text you want to replace with -> open the dialog box again to paste and then find/replace. In InDesign this is not the case
Absolutely. Modal dialogs suck in most cases.
Therefore another, more general request exists:
Try to Eliminate Modal Dialogs