It gives a rough idea of article length without needing to scroll down. Like remaining time on a video.

If it is a topic I’m interested with a two minute read time there probably isn’t anything of value beyond the headline. If I don’t really care and it is a 30 minute read time, there is a high likelihood that I will lose interest before finishing.

Since I read pretty fast, the estimates tend to be higher than it actually takes, but it still gives me something to use to determine whether I want to start reading.