Why are equal signs used to substitute an English hyphen?


I was reading an article about Idlib and the groups that were there on
Wikipedia, and hovered to the language setting to gloss at the title
translations. For Japanese, I saw something unusual in its format. For
example, the rendering of the name of one of those groups is
「タハリール・アル＝シャーム」instead of the usual 「タハリール・アル・シャーム」. I also saw this in manga
character names such as「キルシュ＝ワイミー」. Is using the equals sign in place of
nakaguro common and is it acceptable? If so, is it solely at the author's
discretion?




Technically speaking, this character should be `゠` (U+30A0 KATAKANA-HIRAGANA
DOUBLE HYPHEN), not `＝` (U+FF1D FULLWIDTH EQUALS SIGN), and is indeed used to
avoid confusion with 長音符: `ー` (U+30FC KATAKANA-HIRAGANA PROLONGED SOUND MARK).

From the [Double hyphen](https://en.wikipedia.org/wiki/Double_hyphen)
Wikipedia page:

> In Japanese, the double hyphen (ダブルハイフン _daburu haifun_ ) in rare cases
> replaces an English en dash or hyphen when writing foreign words in katakana
> due to their potential confusion with the prolonged sound mark (ー). It may
> be used to separate a person's given and family names, such as transcribing
> the name of Galileo Galilei as: ガリレオ＝ガリレイ. The middle dot (・) is however
> much more commonly used for these purposes. (For foreign names that include
> both spaces and hyphens, both the middle dot and double hyphen may appear
> together as in Catherine Zeta-Jones: キャサリン・ゼタ゠ジョーンズ.) The double hyphen is
> part of the JIS X 0213 standard, but is not included in more commonly used
> character encodings, such as Shift-JIS and EUC-JP. For this reason, the
> equals sign is frequently used in its place.




Technically speaking, this character should be `゠` (U+30A0 KATAKANA-HIRAGANA
DOUBLE HYPHEN), not `＝` (U+FF1D FULLWIDTH EQUALS SIGN), and is indeed used to
avoid confusion with 長音符: `ー` (U+30FC KATAKANA-HIRAGANA PROLONGED SOUND MARK).

From the [Double hyphen](https://en.wikipedia.org/wiki/Double_hyphen)
Wikipedia page:

> In Japanese, the double hyphen (ダブルハイフン _daburu haifun_ ) in rare cases
> replaces an English en dash or hyphen when writing foreign words in katakana
> due to their potential confusion with the prolonged sound mark (ー). It may
> be used to separate a person's given and family names, such as transcribing
> the name of Galileo Galilei as: ガリレオ＝ガリレイ. The middle dot (・) is however
> much more commonly used for these purposes. (For foreign names that include
> both spaces and hyphens, both the middle dot and double hyphen may appear
> together as in Catherine Zeta-Jones: キャサリン・ゼタ゠ジョーンズ.) The double hyphen is
> part of the JIS X 0213 standard, but is not included in more commonly used
> character encodings, such as Shift-JIS and EUC-JP. For this reason, the
> equals sign is frequently used in its place.

