Ancient post, but couldn’t find the answer to the function of the Patch Button in the SQ-5 manual.
Interestingly, the SQ-5 and SQ-6 manuals are different and downloading the SQ-6 manual and going to page 19 as recommended helped answer the question.
As best as I can tell, for the SQ-5 the button turns off the confirmation prompt you get each time you press on a square to set or unset a patch. So, for bulk edits, press the Patch button. The rest of the time, have it off so you don’t inadvertently change your patching matrix.
I hope this is useful to someone new to this like me trying to work their way through all the numerous buttons and features.