You don't have to show in that competitive, points chasing sense. Not at all. That's not for everyone.
BUT… taking your birds, birds YOU have bred to quality shows, against the best breeders of your chosen variety/breed IS important. It simply peer review. You coop in right next to the others. The judge handles your birds and compares and contrasts them against the others. At a top show, there may be 20-40 other birds of your same variety.
The experience is invaluable. The "chicken talk" is invaluable. Trading notes and chat and putting your own eyes on the other birds next to your own will tell you just how far you've come in your efforts. Finally, the judge will tell you his/her opinion as well. The cost is often less than $5 a bird to enter them for the judging.
The truth is that it is almost impossible to gain this kind of feedback any other way.
Also, we breed birds against the breed standard. Just the "standard". The APA book is entitled the Standard of Perfection. We don't breed to the SOP nor do we have SOP birds, in spite of that being common usage here on this site, but rather we breed to the standard and we aim for having standard bred birds. Just wanted to kind of clear up that terminology. I had to learn this myself, I'm not too ashamed to say. We live. We learn. We grow.