I just want to add by saying that observations of cultivated plants have a huge amount of scientific value that I think is underappreciated by many users here. I am an urban forester and I frequently use iNaturalist to look at where species are being cultivated–this can be a useful proxy of their environmental tolerances, and while I’m not sure there is any research using iNaturalist for this right now, it certainly could be done.
It can also provide useful information to aid identification in the event of unknown naturalizing plants. These observations can serve as an early warning if a given species begins to naturalize before it becomes a full blown invasive species, although this is often obstructed by users who label observations as cultivated based only on the location and species without thinking. If there is ever uncertainty I think it is best to err on the side of leaving it wild or deferring to the observer–I have noticed entire populations of naturalizing plants that have been marked cultivated solely because they are not “supposed” to be there.
Finally, cultivated plants have a huge impact on other wild species, and are particularly useful for identifying host-specific insects such as galls formers. It’s frequently useful to take an observation of the host plant because a correct identification can assist with the identification of the wild species in question. And of course, it’s also useful to know which hosts wild species are able to make use of.
I don’t want to rehash the whole cultivated = casual debate in this thread but one frustration is that there is currently no way to distinguish these useful and high-quality observations from other casual observations, including the ones discussed above where the species is merely for sale and not really interacting with the biome in any meaningful way. Another example would be indoor plants–it can be hard to see what areas Ficus grow on the range maps currently because they are common house plants.
I know it has been said that cultivated plants are not main focus of iNaturalist philosophically, but my view is that they are a part of nature and information about them has value, and could have a lot more value if iNaturalist gave a little more thought to how to better manage them.