A key difference between a queue and a ring group, is that queues can ring out, for the caller, for many minutes, whereas ring groups are assumed to be answered quickly. Whilst, in some cases, this may not be the reality, if you didn’t answer the call early, for a normal queue, the call would be ended by the network, before it reached an agent.
If answer times are expected to be long, Queues are the construct you should use.