I see the differences between business and economy in short haul travel as:
Lounge access
More and/or better in-flight food and drink
Sometimes more legroom and a gap "seat" between you and the next passenger
Priority baggage transfer (sometimes)
Priority for flight changes if your flight is delayed
More ticket flexibility (sometimes)
More points on your card
Depends on the airline and aircraft concerned, as well as the flight length and who is buying my ticket, but it can work out to be "better value" to pay more for business more often than not.