Why do the Hebrew Alphabetic Presentation Forms Exist

[Marius Spix]

Ы is a ligature of Ь and І. Й is a И with breve. They are considered to
be seperate letters for historic reasons. Λ and Α have nothing in
common but part of the shape. They derived from completely different
characters. 

On Mon, 8 Jun 2020 16:23:41 +0900
Wáng Yifán wrote:

> - Whether to separately encode two characters is mainly decided by
> difference in structure i.e. sub-character formation, besides the
> semantics, because Han characters are compositional by nature, unlike
> most phonetic scripts where each letter only means what it means as a
> whole shape (Α is not a Λ with hyphen, is it?).