Because it's about the journey and not just the artefact. If you're not thinking of something that's useful and preparing snippets to share every day you are not practising it. Having to come up with something stretches your imagination and critical thinking skills. What's true for the writer is true for the reader - if you just shared a simple repository with tricks, exceedingly few are going to read that, and the ones who do will forget it. Daily practise is important.

I don't think that's a generous way to interpret it.

I see it more as: every day they will go on the slack channel and pause, wondering "Is there a neat trick I've learned or used recently?" then they share it. It's like a ritual to remember that you can share things because it's easy to forget other people don't work the same way you do. Writing it all at once is difficult (you have to remember a lot of stuff at once) and it tends to go unread.

I also think every single day is a stretch, but it's nice to pause once in a while to think about how you could help other people with something you've learned.

You’re right, a centralized repository would be good too.

Both a centralized repository AND a daily message, especially for new employees, would be ideal, imo!

Normalize chatting and sharing stuff in slack!