Based on my experience as a frequent flier that flies Delta a lot, it isn't. Let me explain. Delta has four tiers or levels. I frequently see Diamond medallion members, the highest category in Delta's frequent flier charade, sit in main cabin. There are few upgrades available. As a Platinum member, a Comfort+ upgrade is a blessing for me. I'm usually way down in the First Class upgrade list. I don't have the Delta Reserve card that could improve my chances at getting that upgrade. I can only imagine what the benefit is for flyers with Silver and Gold status on Delta's loyalty program. A free bag? Consider flying Southwest instead.