The job is small. You are in the middle of something, a piece is worth your time, and you cannot give it that time now. The app should take the piece with one action, keep it somewhere you will find it, and still have it when you get there. Everything else — highlights, text-to-speech, offline mode — is optional.
The job fails in two common ways. The app stores the link, and the link dies before you read it. Or the app stores a queue, and the queue becomes a guilt pile you never reopen. A useful read-it-later app has to survive both.