In practice that fee works out to at most a $500 buy-in for Platinum status on Delta. You can also immediately opt for a $200 travel voucher as your Platinum benefit. I could see why some might think it's worth it.
Starting in 2023, mere platinum doesn’t get you lounge access on international flights, but the affiliate credit cards do. That’s worth $20+ in real value on each international segment (the sticker price is higher, but there’s at least $20 of convenience and comfort to wait in the club over the boarding area).