[ghaff]

There is always diminishing returns to travel upgrades. Maybe $100 (or whatever) gets you a bed but $300 get you a really comfy bed with a nice view. This also applies in all sorts of areas.

>Priority boarding, I never understood the point of.

A lot of it has to do with having overhead space. On a packed flight, you'll often have to check your carryon if you can't fit it under the seat in front of you if you're in a late boarding group.