It’s convenient for players, who don’t need to know anything about networking to play, which is why we all use it despite its downsides. But it always has downsides. Steam networking goes down for regular weekly maintenance and kills your multiplayer session in a lot of cases. If you and a couple of friends are on a train or in a rural area with terrible internet, you can still play with LAN.
But these online connections are in fact DRM. If you need to connect to your store’s servers to play multiplayer, I imagine that reduces piracy compared to being able to copy paste the executable a few times and send it to a few friends that can all play together. Still, I want the guarantee that what I’m buying is built to last, which means no DRM, which means requiring that connection to my store’s servers is not it.