I agree in that it doesn’t need to be required, but I think you’re leaving money on the table and intentionally limiting who can experience the art you’re trying to share with the world.
You don’t HAVE to include more than the basic colorblind option and maybe some extra visual cues, but games that go farther and allow more people to enjoy their product are better products for it.
Souls games are great. I don’t want to ‘get gud’ so I haven’t bought one ever, and with no difficulty drop I probably never will. I don’t have time for that. It’s not a bad game because they don’t have features to make it more accessible to me, but it COULD be a better game if they did.