Letterlike Symbols is a bit of a weird grab bag of characters, most of which are clearly distinct from their "regular" Latin versions, but I do agree that a few of them are pointless exact copies of regular Latin letters.

The fullwidth/halfwidth stuff is a bit of a mess, but you could argue that these are actually CJK characters that just happen to resemble Latin characters (much like how Greek and Cyrillic both happen to have letters that look a lot like the Latin "A"), since they only exist for compatibility with older CJK encodings. This wouldn't be a very good argument though :)