i don’t think this is technically possible. whereas observations have created, observed, and updated dates, and identifications have identification dates, i don’t think there’s a specific date associated with annotations that could be used as the basis for figuring annotations by any time period.
I don’t know how accessible they would be for Year in Review to access, but as an admin I can see created-on dates for annotations, so they’re stored somewhere.
Identifiers are nonprofit volunteers. One of the most effective ways to retain volunteers is to recognize their efforts. Adding annotations to the Year in Review recognizes the valuable contributions of identifiers.
Recognition can drive motivation, as well. You get recognized for your efforts, which boosts your morale, and it then motivates you to do even more.
This all supports the mission of iNaturalist: getting more people engaged with nature.