I’ve been following and participating in this thread, and I think your impression of “rigid ceremony” is mostly a misunderstanding.
Sushi is a special kind of food that many people know little about, so a bit of instruction on how to best enjoy it is helpful. And a sushi chef is a special kind of chef, in one sense much like any other gourmet chef, but taken to an extreme. It takes years of training and a long apprenticeship to become a great sushi chef.
It’s not just about the physical assembly of nigiri, but about careful selection of the seafood and other ingredients, about knowing exactly what flavours complement what seafood, and about skillfully creating elegant presentations. It’s a fact known to all gourmet chefs that an appealing presentation is part of makes great food enjoyable, and sushi chefs take this to an extreme. My favourite sushi bar extends this aesthetic even further with a sushi bar counter and table tops made from hinoki wood, from the Japanese cypress, known for its natural fragrance and beauty. It’s all part of creating the perfect aesthetic for this noble form of culinary art.