If you want to tie flies to catch fish - think size, colour, weight, profile/movement.
If you want to tie flies that are challenging to tie and look nice - think exotic feathers, colour combinations, proportion.
Flies that catch fish can be both.
I have caught salmon on flies that, to my eyes, are the ugliest of creations(simple black & yellow tubes etc.). I have also caught salmon on flies that have taken a long time to tie and would not look out of place in a ladies brooch collection(traditional patterns, temple dogs, intricate shrimp patterns etc.).
Each to their own I say. If it matches the conditions and gives you confidence, fish it. I can now happily fish with the same fly on my leader all day. I used to change flies regularly just because I had not tempted a fish. If you have picked a fly that suits the conditions a change in presentation is more likely to induce a take than a change of fly.
Each to their own, whatever makes you happy.