Having high quality silence and/or music available in my pocket at all times was definitely more of a game changer than I expected.

Using a 8K 55" tv as a monitor.

I usually run it scaled, so I have basically the pixel area of a 4k screen but with retina resolution. Everything is crisp and large enough that even content placed in the corners is easy to read. Truly a game changer for work, so much so that I am puzzled why there are basically no 8k proper monitors available at sensible prices. This TV was manufactured and shipped halfway across the world where I bought it brand new for less than 1000 usd. And its a TV, with a TV OS, remote control, TV tuners and whatnot - HDR even. A normal monitor without all the TV stuff and sensible inputs (I have to use HDMI 2.1) should be even cheaper.