In a way - though unfortunately not a way that is reflected in readership or earnings! - being nommed is more valuable than actually being boosted, as it is the considered judgement of a person who has themselves been chosen to specifically curate submissions in the particular field in question. It's a genuine decision based on merit.
The reliability of the Curator approval decision may well be affected by: unknown internal quotas or ratios regarding certain topics, pubs or authors; that individual's experience/expertise/confidence, especially in the case of newer hires; their workload or mood.
As nominators, we think long and hard about our decisions - and should communicate with writers as to why we feel their piece is/isn't a strong candidate.
Curators are probably under greater time pressure to make each call, especially as the number of nomming pubs has more than doubled in the last year, but I doubt the Curation headcount has.
None of which is any consolation for a writer wanting to ensure the time, care and effort that goes into their stories is reflected in the readership and earnings they receive via the platform's mechanisms.