Tasks are ephemeral, fast and go away. Quick in quick out. Knowledge management is for the more polished things you want to keep. Things that you can refer back to and build on in the future.
To enable this, you can link from Obsidian to your Task Management system. In my case, it’s Akiflow, and I can throw the obsidian link directly in there. Obsidian URLs make this incredibly easy and convenient. It is similar to how at work I don’t put the longform documentation in Jira. I put the documentation in a Notion page that I then link to Jira, because soon that Jira ticket will be gone, but I want to be able to keep that knowledge.