Hi there. Serverless Dashboard also provides additional functionality that consumes credits if used. By default, every organsiations is provided 2 credits as a part of the free tier to try these out if they wish. However, as you say, if your org is under the $2 million ARR limit, you do not need to purchase credits to cover your V4 licenses and you can deploy as many as you need.
Thanks for bringing the potential confusion to our attention though; when you have been looking at something for months it will always make sense to you so getting an “untainted” opinion on whether something is clear or not can be helpful. We will look at seeing if we can make things clearer in that regard.