Also, you spend a day off and if the channel is active, it's a chore trying to get back on track if the team does not have better suited communication methods. Quasi real time discussion on a bug is great, but it's better to add the final findings on the ticket/PR. Same for features, draft up a doc afterwards. Slack and the lack should be considered transient and important information put on more permanent and more brows-able forms (Wiki, document repo, ticket system,...).