Right now there is not a single map making software which uses vector assets, but at least OWM is the only one supporting vectors.
To start/focus with/on pixel assets is absolutly fine and the reason has already been told by Kanchou in the linked thread at the top:
The thing is:They tend to not look as good as png because it's harder to get the "painted" feel to them.
- People who know vector images understand that and doens't have the requirement for 1:1 copies of pixel assets.
- People who are interested in vector assets are mostly going to create big maps, so their (and my) demand are assets that are able to get bigger and not as tiny as possible.
In the OWM gallery is this map:
Those mountains would be awesome just in black & white, without a filling colour - same for the trees.
But an artist may have a better idea how vector mountains and trees should or need to look like.
So my proposal is to start just with a set of vector assets to be able to create black & white maps.
I wouldn't mind if you made that a feature of the extended version of OWM.
I just really really want to create a map which is 100% made of vectors.