The Chase Sapphire Reserve and other large annual fee cards generally only make sense for very frequent flyers who are pretty sure they’re going to get more in card benefits than the annual fee.
The airline specific cards with about a $100 fee- their sweet spot is people who fly the same airline 3-5 times a year and like to check bags since you get more value in bag fees than you pay in annual fees. They can be worth the sign up bonus for once or twice a year flyers if the offer comes with the annual fee waived the first year.
The no annual fee airline specific cards generally will give you a sign up bonus roughly the same number of miles as a domestic coach ticket. They’re not the most exciting cards from a bonuses and benefits standpoint but they can be a useful way of dipping your toe into the award game pond and seeing if it’s for you.