Is there any linguistic value behind encircled katakana letters?


Today I've learnt that in Unicode there's a separate block for katakana
letters enclosed in a circle - all of them, apart from ン. Then I've realised
that the logo of this particular stack is a letter in circle as well
[![https://en.wikipedia.org/wiki/Katakana](https://i.stack.imgur.com/F1fPn.png)](https://i.stack.imgur.com/F1fPn.png)

My question would be: What is the actual usage of such symbols which is that
important that encircled kanas are introduced to Unicode and why nevertheless,
an ン is not a thing.

There's a similar question about
[kanji](https://japanese.stackexchange.com/questions/50511/usage-of-encircled-
kanji) however it does not cover katakana.




Just like other symbols in [this
answer](https://japanese.stackexchange.com/a/50519/5010), these encircled
katakana are mainly used to prefix items in a list. For some reason, Japanese
people historically used to like encircled characters, just as English
speakers like to use letters enclosed in parentheses (`(I)`, `(a)`, etc).
Japanese letterpress companies had many movable types for encircled
characters. That said, very few people use these encircled characters today,
partially because of the longstanding encoding compatibility issues explained
in the linked answer.

ン was not included in the character set probably because ン is a special sound
that never comes at the beginning of a Japanese word. It's unlikely to list
50-ish items using this method, anyway.

I guess the logo of this site was inspired by
[hanko](https://en.wikipedia.org/wiki/Seal_\(East_Asia\)#Japanese_usage).




Just like other symbols in [this
answer](https://japanese.stackexchange.com/a/50519/5010), these encircled
katakana are mainly used to prefix items in a list. For some reason, Japanese
people historically used to like encircled characters, just as English
speakers like to use letters enclosed in parentheses (`(I)`, `(a)`, etc).
Japanese letterpress companies had many movable types for encircled
characters. That said, very few people use these encircled characters today,
partially because of the longstanding encoding compatibility issues explained
in the linked answer.

ン was not included in the character set probably because ン is a special sound
that never comes at the beginning of a Japanese word. It's unlikely to list
50-ish items using this method, anyway.

I guess the logo of this site was inspired by
[hanko](https://en.wikipedia.org/wiki/Seal_\(East_Asia\)#Japanese_usage).

