The aura around optional bosses in FromSoftware games has always astounded and their distinction as foes who can be inadvertently undiscovered, circled back to later, and ignored completely make a lot of them far more compelling than a boss players have no choice but to eventually confront. This can make them more special or revered with FromSoftware free to design them to be as difficult as possible if it wanted because they dont need to abide by the same constraints as a boss who players are required to defeat in order to roll credits.