Courtesy chaos, including Pokemon from lower / other tiers. See e.g. https://www.smogon.com/dex/sm/formats/nu/, scroll down to "Other Pokemon with Strategies".
More than a little convenient especially for non-usage-based tiers like DOU, Monotype, and OMs.
More than a little convenient especially for non-usage-based tiers like DOU, Monotype, and OMs.