Discussion posts are a good idea, in theory. But in reality, they just end up being one of the worst, most miserable experiences.
The whole point of a discussion post is to bring classroom discussion online. The whole thing is that you are given a prompt that you have to reply to, and after that you have to reply to a few other people. This is a way to either discuss a topic, or to get feedback from other classmates.
In theory this sounds like it would work, and it does, for the most part. For work in progress check-ins, you usually do end up getting some valuable feedback. However, nobody really wants to be doing these discussions, so they all end up feeling the same.
You aren't expected to reply to your replies and start a conversation, you're only expected to reply to a few other classmates. There is no benefit to trying to argue a separate opinion. As a result, most people just end up saying things like "I agree with you when you said that" or something similar.
And the worst thing is sharing work in progress check-in posts, especially if you're using Canvas. Some people just have a really hard time replying with their work in progress. Some people like submitting the raw project file, instead of just a screenshot. And for some reason you cannot open an image in a new tab on Canvas without downloading the image. Fun!
And for large, complex projects the check-ins are ever worse. You have to reply to a certain number of people by a certain date, however most people are hesitating the project, so you basically have to wait until near the end of the due date before there is anybody to reply to.
Plus, when you do it feedback, it's usually just someone telling you "I like this, keep it up".