I've used the late and missing policies in the new gradebook for the past few weeks. What I'm discovering is that the late policy in particular is too cumbersome to be useful. Not every assignment I give is something that I expect students to make up. Bell Work assignments, for example (which I give every day) do not need to be made up by absent students. I give a bell work every day. However, under the late policy, these assignments lose point value. I found myself having to go back in to the gradebook and excusing absent students all the time. It turned out to be more work than it was worth.
If I could apply the policies to particular assignment groups (like "homework"), that would be great. It would allow me to differentiate between which assignments I wanted to have the policies apply to and which assignments I didn't require students to make up.
This is a great idea, and other people have thought so, too! I'd encourage you to add your voice to https://community.canvaslms.com/ideas/10441-separate-late-policies-for-individual-assignments so that our product team is aware of your workflow and need for this feature.