Unless you really need that extra processing power, it would be a waste of money. If you're doing video editing (in which case you most likely would have went for a 15 inch) I would highly advise against it. With day to day tasks you'll most likely notice no difference at all. For perspective, I have a 2013 15 inch and a 2018 15 inch. Day to day tasks are almost identical. The only time I see a real difference is when I'm working in DAW's, which the newer model basically allows me to load more midi and audio tracks without the computer slowing down.
Hope this is of help to you.