Thoughts on Pop-ups

(I’m not sure if this is the right space for this!)

Hello, fellow writers! I have heard a lot lately about people recommending pop-ups for your blog/website. I want to gain more subscribers, and I’ve heard that pop-ups are useful for that, but I also know from personal experience that they can be annoying at times. I don’t ever sign up when I encounter a pop-up. What are your thoughts on pop-ups? Pros and cons?