It's not actually necessary if you use a lot of it, but yes, a lot of people do in America. It got caught up in some health scare or another and people said "it's dairy, right?"
I don't even understand the butter tray in modern fridges. When I was a kid, that tray was basically in such a way that the cold didn't really reach it so the butter didn't get hard. These days that isn't the case. What is the point?
Weird. I leave my butter out all the time and never noticed it going rancid. But we use it up pretty fast once it’s out. Also we get unsalted butter that’s heavily pasteurized so maybe it last longer? Today I learned.
How to Store Salted Butter
If salted butter is your go-to, it can be stored on your counter for a few days! Leaving a stick or two out at room temperature will do no harm if your kitchen is kept at 70 degrees or cooler. The salt content helps keep butter fresh, even out of the refrigerator. Once it’s softened, salted butter should be used within one week.
However, if butter is left out at room temperature for several days, the flavor can turn rancid so it's best to leave out whatever you can use within a day or two.
Nah man. I thought this. My butter went bad and I didn’t realize until I ate a lot of it. I was putting it on bagels I was getting and I kept thinking they were mixing like rye seeds in there. That was the closest approximation I could conceive of because I thought the same as you.
Nope. I kept eating sour butter. It was fucking disgusting. Keep your butter in the fridge.