I only use it to sell common flowers at night. I don't have a trash can on my island and often decorate after hours, so that's where my red and white roses, red lilies and red tulips go.
I was very much the same until a few days ago when I finally got a trash can.
I'm a night owl in the Northern Hemisphere and since I don't have as much daylight hours to play, I've either hoarded or sold my low value items... Like shells and flowers.
I almost always use the box, but I only really get to play at night most of the time, because I'm too busy during the day, so I check shops while waiting for skype calls to go through I love starting a game the next day and having Timmy and Tommy call to say I made like 200.000 bells the night before.
I've never used it. I had a considerable amount of storage left in my house still so I typically just keep everything in there and then sell in the morning!
I actually don't play much anymore after Nook closes, but I don't sell things in it. I sometimes would use it to get an estimate of the sale price of items. Need to know if those fish and bugs are worth keeping for Flick/CJ
I did at the beginning of the game, but I don't now unless I want to hit a Nook Miles+ goal. I have enough space that I can just hold onto anything I want to sell the next day and get full value for it.