For better or worse human beings are creatures who like to categorise things. This is how we deal with complexity, even if the categories are not always optimally chosen. Marketing departments inevitably start off with pushing a category for a product and suggesting this is it's "best at" or indeed "only option" angle. This allows we category seeking beings to remember it better, and indeed, provides a secure "beachhead", even if very specific, which the product (~language) can dominate and from which it can credibly grow. Nim does not seem to have this beachhead, and basically is therefore diluted across categories and is harder to remember. I therefore agree with the original post that Nim does not have unique selling point if you will.
Separately, "marketing" is of course a term loaded with negatives, but it is essentially about communicating a benefit in a very crowded and competitive environment. That benefit has to be very clearly enunciated and pushed, and if it is a clear and simple message, then it will be effective.
It's a secondary concern that a language is a polyglot at all sorts of use cases, is good at everything. It first has to have users. Users have lots of choice so you're best off giving a small subset of them the idea that this is the perfect tool for their specific use case, and grow from there, than telling everyone this is good at everything, even if that is true.
Unfortunately the best all rounder is often forgotten if she/he's not number one at something.
TL;DR: In a crowded and complex marketplace marketing's segmentation methods are unfortunately needed.