I do both. I use Obsidian to maintain lots of notes and links and such. But I also carry a fountain pen and a notebook in my pocket. I find when I write stuff down in there I tend to remember it more. I also carry an A5 notebook at work to take down work notes and track my todo's. More productive, looks better in meetings, and I'm less likely to get distracted by notifications or the draw of apps/social-media.

Lots of times I'll do a drawing of dimensions or an idea, then I'll take a picture of that and throw it in Obsidian later. Also if it's a note that I want to keep later I'll transcribe it into my digital notes.

I just enjoy the act of writing and getting to own a pen that I won't just lose or loan away. I'll also pick up old notebooks sometimes and be reminded of things I wanted to do or ideas I had that got missed, and the reminder is way more tangible and impacting that being reminded by found digital notes. It comes with the tactile memories as well.