It doesn't use the word, but "access to any substantial set of the features or functionality of the software as a hosted or managed service" is a specific kind of competition, and who is a competitor can change at any time depending on what functionality Elastic adds, even if you had reimplemented some of the enterprise functionality in a private fork.
Imo "substantial set of features" is pretty ambiguous. If you're using search software, then you have a search use case in your product. At what point does your product cross the threshold into a competitor?
It seems risky to use in anything exposed as a customer facing feature
Search may be 10% of your software but what if your software is a managed email provider (or really anything) and you're pretty much exposing Elasticsearch directly through a minimal interface?