I started using Obsidian about two years ago and it has literally change my life. I now have all of my knowledge inside, and every single day I find new ways to use the app and also new knowledge inside my own notes - as everything is connected.
And this last point is the number one reason for using Obsidian: Every time I add some new information, it connects to old information, and make old information resurface because of backlinks. Brilliant.
I have started THINKING differently after using Obsidian, which is a testament for how clever this app is.
And everything is "just" text files that easily fit on flash drive if I wanted. Futureproof and light.