Better than paying 200USD for a EU short haul business class upgrade I think for a comparable flight distance...I'd happily swap for the EK seats in J and ditch the lounge access. For a 1.5 hour flight I would turn up to the airport at T-65 and go straight on board. Of course, I think it is a little bit cheap not to provide the lounge and chauffeur drive of EK, but I think the offer is relatively transparent so I can't blame them too much.

The point is these emails are there to try and get additional revenue out of you - you are guaranteeing the J seat. If there are enough people in Y who don't care about lounges and chauffeur drive but who only want the seat, they may think this is a good deal and do it. It's automatically generated and any ill-will they might generate from irritating a Skywards member is in their calculation going to be outweighed by additional revenue.

If you think you'll be able to get an upgrade closer to time using miles, then of course you should ignore the email. There may be seats available in J class though, but the load controller may be holding them back in order to get cash revenue instead of using miles - and may only let you use miles at the last minute, which gives you 30 minutes of lounge access, maximum.