If I am awarded 40,000 airline points from, say, Southwest, is there a website that can tell me what I can exchange for those points-what items, flights or upgrades they can get me? How can I tell if going for a certain airline for points is a good thing if I don’t know what they are really worth?
Well, for Southwest specifically, you can browse flights priced by points or the rewards point store without needing an account: Redeem for More Rewards
If you’re looking to compare to other airlines, I’m not sure what options might be available.
This is a good resource for comparisons across airlines: What are points and miles worth? TPG’s February 2023 monthly valuations - The Points Guy
I am not sure about using points for items, though. I think, as a rule, you get the most value using points with the company that issued them rather than exchanging for 3rd-party goods/services. If I’m wrong, happy to be corrected.
If you’re more concerned about credit card signup bonuses than choosing an airline to fly frequently with, https://www.reddit.com/r/churning is your friend.