Now, it is possible I could hide every column manually past the point I want to end at, but does that reduce the number of rows and columns that need to be calculated? Hiding also doesn't stop scrolling significantly past the spreadsheet.

The main reason I'm wondering this has to do with processing. Would it take less processing effort if there were less total rows. Second reason is just having it look cleaner.
For example, if you accidentally select all cells and hit insert table, it might freeze the program (I waited for a few minutes before giving up and just restarting and just redoing what wasn't restored).