By the way, if you’re still wondering about the usefulness of IDing unknowns, I just checked the numbers and there’s currently 12,991 pages of them, at 30 observations a page, that’s about 389,730 observations - that should be enough to stay busy for a while ;)
Also, it’s so much fun when you pull something out of the unknown pile and it then ends up getting identified as a very interesting or rare species: https://forum.inaturalist.org/t/best-unknown-finds/29009/6
Edit: Forgot to add, there’s another easy-to-do task that’s super helpful, which is adding annotations to observations that are missing them, even the research-grade ones. You can search for observations that need them under the “more filters” section of the identify window. Examples would be Plant Phenology (Blooming, budding, fruiting, no sign of flowers?), evidence type (actual animals vs observations of their tracks or scat), life stage (adult insects or larvae?). Not many people add them but they’re so useful for anyone trying to search for observations.