Why is playing music in a playlist in order a Spotify premium feature?

I recently got Spotify and I noticed that you can’t play your songs in order? I just find it confusing cuz that feels like a core part of really any music streaming app. I mean I was making playlists on YouTube before and could do it. I’m not to annoyed since Spotify is still a good app and it’s more of a mild inconvenience but im still curious.