Message has one underlying data model: a conversation. The Shared inbox view and the Ticket queue are two different lenses on the same data.
Shared inbox
Chronological, channel-mixed, optimized for fast turnaround. Most chat-heavy teams live here. Real-time, auto-refreshing.
Ticket queue
Prioritized, status-grouped (open, pending, resolved, waiting on customer), optimized for SLA enforcement. Email-heavy and B2B teams tend to live here.
Switch on the fly
Toggle between the two views with G then I (inbox) and G then T (tickets). Most agents pick one and stay there. Pick what your team is built around.