Would the US Skating Championship serve any real sporting purpose if it was not also used as the World and Olympic qualifier?
Absolutely.
Suppose, for the sake of argument, that the rules for world team selection and Olympic team selection were changed so that once a skater or team had established themselves on the international circuit they can have the option skipping Nationals without decreasing their chances of being selected for those teams.
Maybe Nationals would even be held at a different time of year (e.g., in April, after Worlds), when it would make less sense to think of it as a direct qualifier for Worlds.
What would be some of the real sporting purposes that Nationals would serve in that case?
1. To name a U.S. champion in each discipline for that season.
This, obviously, is the single most important purpose, indeed the raison d'etre, for holding a national championship each year.
To the extent that the US title continues to hold prestige, US skaters with strong international results would still be motivated to compete for that title, even if it would have little to no effect on the chances of their being sent to Worlds.
2. To establish national rankings by providing one central opportunity for all the skaters who qualified for Nationals (through regionals and sectionals or through international byes) to compete against each other in one event.
This is the only way for newcomers to prove themselves against the established international skaters. Otherwise, how does one become an international skater in the first place?
3. To provide a basis for the international committee to choose which skaters to send to international events other than Worlds and Olympics.
Depending on the timing, level, and the importance of each international event, Nationals might be used as a direct qualifier for the international or as a way of narrowing down, e.g., which ten or twenty out of the hundred or two hundred best age-eligible female skaters in the US should be considered for JGP assignments next summer, perhaps with additional competitions or monitoring in between also taken into account.
4. To name national champions in each discipline at the novice and junior levels.
5. To establish which skaters to provide some funding for the following year, invite to federation-sponsored training camps, or otherwise support with various benefits that have to be earned through successful competition within the US.
If it were primarily used to showcase pretty costumes and nice music would it be little more than a pageant? Would Natls hold any excitement at all if we already more or less knew the make-up of our National team?
In addition to the above functions that depend directly on Nationals results, there are also other functions that Nationals serves that are not directly related to the results but that are a little more serious in their relation to advancing the sport than just showcasing pretty costumes and nice music. A few examples:
*To allow skaters and coaches from various parts of the country to see firsthand the standard of skating and the kinds of technical and choreographic choices being made by the best skaters from outside their own part of the country.
*To allow ice dancers and pair skaters, and singles skaters who might consider switching to dance or pairs, to see what opposite-sex skaters are out there competing (in dance, pairs, or singles) who might make appropriate dance or pair partners, should they become available as such.
*To allow officials who might be considered for international appointments to show their skill by officiating at Nationals.
*To allow officials a step or two behind that level in the process to trial judge, etc., at the national level.
*To hold educational seminars and meetings for skaters most likely to earn international assignments in the future, while they're already all in one place.
*To provide a reason for former skaters, including former champions, to gather in one place to keep in touch with each other once a year.
*To present certain awards (Hall of Fame inductions, Scholastic Honors awards) at a national event
*To give fans one big central event at which to be able to watch most of the best skaters in the country all in the same place.
*To allow officials on various committees needed for running the business of the organization, much of it conducted by e-mail etc., to have an occasion to meet in person each year.
And, yeah, some attendees do enjoy the opportunity to admire each other's costumes or off-ice fashion. But that's incidental.