It's not. It's an addiction. It's shovelling snow, it's a quest for feeling accomplishment without effort. It's more fuel for being constantly connected, for constantly thinking you're progressing and accomplishing by hitting that email archive button, or scrolling through reams of meaningless text, or fiddling with your spreadsheet layout. It's no better than scrolling through reddit, then closing it to scroll through twitter, then opening up reddit again.
It's really hard honestly, but these days I open up email and slack, clear them, then close them. Both my phone and my computer are permanently on DND, so no notifications bother me. When I'm done with the work day I make sure that nothing work related stays open and that no one can contact me unless it's an emergency. I'm considering splitting my one login on my laptop into two, a work and a personal, and hard-blocking HN etc on the work one, and hard blocking work on the personal. Or using Bootcamp and moving all my personal computer use to Windows.
My Dad always told me that you should have an hour a day and a day a week to yourself. When I was younger I laughed that off. These days I struggle to make it my minimum ideal.