When using a non database-based queue you'll have to find another mechanism to make sure your operation is still atomic.

In other words you can end up in a situation where a record is inserted but the job to work on it is not enqueued, or worse - that an insert fails but the job to work on it is enqueued.

Point 2 is still necessary despite idempotency imo: lets say some value is updated to "a" and then to "b", enqueuing two jobs. If the request to update "b" runs before "a" then your receiver will end up with the wrong value. Same if the initial request to update "a" fails.