What is meant by Western premium domain names?

Below alphabets are considered as premium letters in English language, specially by domain name investment community.
A,B,C,D,E,F,G,H,I,L,M,N,O,P,R,S and T (17 of the 26 Alphabets)

Per example name like ABD.in is considered as a western premium domain name , also DPR.in also considered as a western premium domain name.

Non premium Letters:
J,K,Q,U,V,W,X,Y,Z (9 Letters)

It is the belief of domain name investment community that western premium domain names are most sought after compare to non premium domain names however this has been proven wrong in the 4L.com domain names with the raise of Chinese premium (CHIPS) domain names. In 4L.com category CHIPS are more valued by domain investors compare Non-CHIPS.
At the same time western premium domain names are in general valuable across many other categories of domain names and universally accepted by domain name investment community.

Please note from end user point of view this logic is not applicable, a domain name they need is the most sought after for them. Its just domain investors who believe in the principle based on the years of personal experience they have gone through in trading domain names , hence one can argue this is just a myth. 🙂