You are more than welcome to chat about code with your fellow Learners in Slack!
But you will not receive support from Technical Coaches, Section Leads, or Support team members in Slack. Slack is a place to casually chat amongst students, not a place to escalate issues to members of the Learn team.
And in general, we do urge students to pose lab and lesson specific questions on Learn, for a couple of reasons. Our Technical Coaches are on Learn, and will be able to assist you there (for students in a supported program). The Learn team is not officially in Slack looking for questions or issues.
Also, keep in mind, your question will have more reach on Learn, as not everyone in the Learn community is in Slack. By asking the question in Learn, everyone that has answered the question is pinged, and the question is automatically tagged with the associated lesson, making the context very clear.