- 0041 LATIN CAPITAL LETTER A
- 1D400 MATHEMATICAL BOLD CAPITAL A
- 1D49C MATHEMATICAL SCRIPT CAPITAL A
- 1D4D0 MATHEMATICAL BOLD SCRIPT CAPITAL A.
I read that Unicode tries not to encode character presentations.
I believe the question is asking why A, 𝐀, 𝒜 and 𝓐 have different code points when they are the same character in different fonts.
The answer is that they are not the letter A in different fonts. They are different characters in a single font (assuming the font includes them and they can be displayed: if not, then a substitution might occur).
It is a more extreme example of the phenomenon demonstrated by Latin A at 0041 and Cyrillic А at 0410.
These characters are needed for mathematical formulas to display the way mathematicians expect them to. The alphabets encoded at the other code points are only basic alphabets, and don't include for instance ÀÁÄÂÆÃÅĀ.
For this reason, you're advised it's bad practice for accessibility to use these letters on social media, Twitter or other platforms which don't have character formatting, as screen-readers used by blind people can't read them.