Filters are necessary and required because they hide certain submissions from users who don’t want to see/read them or would be bothered by seeing/reading them. Filtered submissions also do not show up for guests or minors who do not have an account that may happen upon the site, thus keeping the site safer from harassment.

Tag are not required, but are used to find submissions. If your works are not tagged properly, they cannot be easily found by those who may have an interest in what you're drawing or writing.