These specials exist for one reason: to show you what the visual novel's uncensored scenes actually look like. The show doesn't pretend to be anything else. For people who finished the main series wanting more of these characters in situations with zero narrative justification, this is exactly the transaction you signed up for, delivered without apology or pretense.
The Eden of Grisaia: Grisaia no Tokuten is a set of five short specials from 2015 that came bundled with the Blu-ray and DVD releases of The Eden of Grisaia. As extras rather than a standalone story, they lean on comedy and ecchi humor, giving viewers of the home release a lighter bonus alongside the main series.