It's bonkers if you don't need it, just like JSONx (JSON-as-XML) is bonkers if you don't need it. But standards aren't for a single individual need, if they were they wouldn't be standards. And some people DO need these variations.

Take your argument about order of operations or algorithms. Just because you might not need to do it in an alternate order or use a legacy (and broken) algorithm doesn't mean nobody else does. Keep in mind that this standard isn't exactly new, and isn't only used in startups in San Francisco. There are tons of systems that use it that might only get updated a handful of times each year. Or long-lived JWTs that need to be supported for 5 years. Not going to replace hardware that is out on a pole somewhere just because someone thought the RFC was too complicated.

Out of your arguments, none of them require you to do it that way. Example: you don't have to supply d, dq, dp or qi if you don't want to. But if you communicate with some embedded device that will run out of solar power before it can derive them from the RSA primitives, you will definitely help it by just supplying it on the big beefy hardware that doesn't have that problem. It allows you to move energy and compute cost wherever it works best for the use case.

Even simpler: if you use a library where you can specify a RSA Key and a static ID, you don't have to think about any of this; it will do all of it for you and you wouldn't even know about the RFC anyway.

The only reason someone would need to know the details is if you don't use a library or if you are the one writing it.