One of the best inventions that has come to the cookie world has been the invention of disposable tipless decorating bags. When I started making cookies 10 years ago I used Wilton brand decorating bags. They were expensive and thick, but I didn’t know any different and they got the job done.
Tipless bags came out about 5 years ago. I ordered some to try and they quickly became a game changer. They were comfortable and easy to use. I still used tips and a coupler because that is what I am used to.
Using a coupler allows you to change out your tip without having to change your piping bag. Typically I use a PME 2.5 tip to outline and a PME 1.5 or 2 to add details.
The biggest difference I found when I use a coupler and a tip is I have more control of my icing. That’s a big deal since I want the straightest line I can achieve. I do not use a tip when I am flooding my cookie! For flooding I use a tipless bag.
Definitely try both methods to find what works best for you; tipless and tipless with a coupler and tip.