The title says "paid revenue seats", but as we all know, J seats have been available for years at the same price as deep-discount economy, adjusted for the seat size, etc. Typically a 3:1 ratio or so because that's how big a J seat is relative to a Y seat in terms of aircraft space footprint. And without the privileges that were traditionally attached to full-J, such as flexibility, refundability, etc. When you throw in the lounge access, baggage allowance, the meal, etc., AC often sells J seating for cheaper than the cheapest Economy seats.
Perhaps the OP should clarify if this was a deep-discount J ticket, or a full-fare J ticket?
If its a deep-discount J ticket, I see not a lot of a big deal here, bottom of the proverbial totem pole, just like an deep-discount Y ticket. If it was full-J, its definitely a different story.