I don’t think it’s a mess; it’s a better option than in many other places whereby the fare is higher even if you have a Multi-ride Pass, at least a lot of people will benefit in that they are not going to pay more at all compared to LU.So paper travelcards can be used on the heathrow tfl rail? But it wont be in zone 6 for pay as you go fare purposes? What a mess.
What is a bit of a mess however is the off peak fare to Paddington is less than to any other station in Zone 1.