I think they are similar, but Daily 3 adds the structure of Daily 5 to how the math workshop is set up. Here's a link to a video of a teacher setting up what she calls math workshop, by using the I-charts and 10 steps to independence.
I think using the same language with as as they've heard with reading/writing leads to that congruence of curriculum that is so important.
https://www.thedailycafe.com/articles/setting-up-math-workshop