And yeah, there's something about being able to touch them, move them, etc.
Whenever I use it, I can't help but feel bothered by the finality of the act of writing in ink. Since we only use index cards when the task becomes too complex to hold in our brain, it also means that we often need to re-organize our thoughts about the task several times. The act of writing (as opposed to typing in a computer) doesn't seem conducive to that kind or re-oganization.
This does a couple things:
1) There's something satisfying about physically moving a thing 2) I can get a quick visual representation of the balance of my work. Am I conspicuously low on a certain type of project in the queue? If so, why? 3) When they're done, they go in a pile of either successful or unsuccessful (I'm an academic, so for example a rejected grant is unsuccessful). When I need to work on my annual report? I just grab 2018's successful pile and it's an accounting of what I've done.
Personally, I like the finality of committing something to ink. If it needs to be changed, it's not as if index cards are expensive, but I like there being a sense of solidity to "What we're doing".
http://williampietri.com/writing/2014/simple-planning-for-st...
And here's how we used them to run a startup for ~2 years:
http://williampietri.com/writing/2015/the-big-board/
You're not alone in being bothered by finality. If I sense any of that, one of the first things I have people do is test their pen on a card. Then I have them tear up that card. Then, later, I'll have them write an obviously too-big planning item, like "world domination". We then tear that up and break it down into smaller cards.
With a little practice, people quickly learn that cards are temporary, just tokens that represent conversations. And they also learn that reorganizing their thoughts is good and beneficial, a sign of progress. And personally, I think it way, way easier to reorganize a stack of index cards than anything in a computer.
One of the especially interesting things to me is that computers do make certain things easier, but they're often things that I'm reluctant to make easier. E.g., computers can store effectively infinite amounts of stuff. I once saw a ~10-person team with a bug database that had thousands of open items. A database like that is way worse than index cards. It was just a big soup of sadness; people struggled to find ways to stay focused on what really mattered. Eventually a new product manager had to declare ticket bankruptcy and start fresh.
With index cards, requiring manual manipulation and physical space forces people to be more practical, more reasonable, more aware of what's going on. We can only keep so many things in mind, and we can really work on a much smaller number of things than that. Matching those human limits to physical limits in planning tools can produce much better results.