This is actually what started me down this path a while ago. I had to do a full text search feature for some text of questionable sources, and some users had taken to using the full width characters for emphasis (I think, they clearly had rules in their head for whey they'd use it, but I didn't know what the rules were). There are libraries that can handle the official Unicode normalization rules, but users don't exactly always pay attention to the official rules, so I get to start finding all sorts of weird little corners of Unicode.
Though, as I understand it, the full-width characters are there not for any modern use cases, but for historical reasons having to deal with older character sets.
I don't think there's much call for fullwidth Latin characters for that purpose. Ordinary use means typing with whatever your input method gives you. This is generally not fullwidth characters.
A clean grid would be desirable in formal use, but formal use means trying to avoid Latin characters as much as possible. It's generally possible. Plaques and the like are much more likely to say e.g. δΊγδΊγεΉ΄ than to say 2020εΉ΄.
Grids are not just for formal use, they're useful any time you want to have aligned text, e.g. if you want to write a markdown table mixing Latin and CJK characters.
And I doubt you'd want to eliminate all formal uses of Latin characters. E.g. a plaque about a person would likely want to use their preferred name, which might be in Latin characters.
I think the full adoption of different alphabet styles as independent unicode glyphs is, overall, a conceptual mistake.
But, note that the identical process, much earlier, is how we got separate capital and lowercase forms. Writing systems never do that when they're developed.
Spacing was used for emphasis in blackletter, and consequently persisted in roman in German even after other means (e.g. italics) became common in other languages. https://de.wikipedia.org/wiki/Sperrsatz
