The tag has a lot more fine-tuned control available, like renaming the query parameter, filtering on fields and collections, and so on. You can read more about it in the search results tag docs.
However, the linked documentation page doesn't provide any information on how results can be filtered by fields or collections.
The main Search page (https://statamic.dev/search) says:
However, the linked documentation page doesn't provide any information on how results can be filtered by fields or collections.