Both the scheduler and queues feature, essentially help with the same thing - advance-scheduling posts to be automatically published at a later date and time.
A. Scheduling posts using the Scheduler feature on Zoho Social, lets team members decide their own time and date for the post to go live.
B. If you choose to publish it using a queue (SmartQ or CustomQ), the post will only be published through the time-slots displayed within the Queues tab.
In case of SmartQ, time-slots are auto-generated based on when your audience is likely to engage with your Brand. CustomQ slots are part of a schedule set up by the Admins of the Brand/Portal, in order to maintain a defined publishing routine for your Brand.