People likely just don't know that it is the same price for Priority Flat rate.
Also, it's not terribly uncommon for folks to see something in an ad and copy and paste what they see without much thought behind it.
Hard to say. I think it might be a lack of knowledge. I always specify U.S. sales only. I got a quick education once when I initially declined to sell a knife to a gentleman from Puerto Rico. He very courteously explained to me that Puerto Rico is a U.S. mailing address. He got the knife, and although I nearly died from acute embarrassment, I survived and came away a little bit wiser. I like to think that perhaps some of the folks you are referring to are just uninformed like I was.
I think people just think it’s cool to write CONUS - makes them feel cool and special. It’s completely wack and a sign of being unaware of many things. CONUS! durrrrrr
It’s the same as “You must comply with your local laws....” It comical reading some of these sale adds.
If I click on a sale add and it’s got paragraphs of mumbo jumbo I usually just skip it.
Back on topic.... yes, Flat Rate will get to AK, HI, and all territories.