“client” here may refer to a backend app server. So you can have 10-100s of backend servers inserting into a same table without having a single authority coordinating IDs.

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morshu9001 a day ago | parent [-]

That table is still a single authority, isn't it? But I guess fewer steps is still faster.

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tracker1 a day ago | parent [-]

Except if you're using a sharding or clustering database system, where the record itself may be stored to separate servers as well as the key generation itself.

	▲	morshu9001 a day ago \| parent [-]
		In those cases yes. There's still a case for sequential there depending on the use pattern, but write-heavy benefits from not waiting on one server for IDs.