I have a friend who uses the Etsy reader because it helps her presence on Etsy by increasing sales in her shop. For me, that is not a factor. Plus, I do not like the fact that it makes me subject to Etsy TOU which means I cannot directly market to those customers unless they explicitly sign up for my emails. Similar to why I don't like Pattern by Etsy, it means I am doing work for the Etsy brand instead of my own.
Whatever card reader & POS system you choose, be sure it is right for you and your needs. Below is a breakdown of the three I researched. I know that Intuit also has a card reader / POS system, but I am not familiar with it so you may want to explore that as well.
Happy Market Day season everyone