A Denial of Service attack could be mere KBs per a hour. If they trigger a heavy API endpoint on the target service, that may be enough to take the service down

A Denial of Service attack could be mere KBs per a hour. If they trigger a heavy API endpoint on the target service, that may be enough to take the service down. The Distributed part just means multiple machines are attacking at the same time. No part of a DDOS requires the throughput to be gigantic, although the big ones are typically the ones you will find in the news. One possible aim of this attack is to either burn through the bandwidth quotum of the source servers, or to use so much bandwidth that it becomes unaffordable. This could be done very cheaply with just a single or few attacking machines. Most datacenters and hosting providers have bandwidth limits or start charging after a certain amount, and too often the company being attacked only finds out when they receive a bill they can't afford.