Agreed upon motions can be ruled on without a hearing. Contested motions for the most part will be set for hearing. It's not really a waste of time. Some contested motions require testimony. A motion to dismiss is a motion based on the pleading alone, so a hearing on that type of motion includes only legal argument, but a motion for continuance may well involve contested factual information, and testimony may need to be taken.
"Oral argument" is a phrase not used in the trial courts at all, but applies specifically to appellate cases, is a different, formal type of argument, and is ordinarily requested by a party, although the appellate panel can set it even if no party requests it.
There are different rules for all these types of motions, and different standards may apply in different types of proceedings.
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