<I doubt your "For people that care about typography in their writing" claim has much relevance.>
An reply that carries some arrogance. Your are technically correct about mono spaced fonts. People who write using Times Roman probably don't care. However, a reasonable view held by many is that a period is a full stop, a pause to complete a thought. Writing that requires reading comprehension above the 9th grade level is enhanced by two spaces. Some courts still specify it. The Unites States Dept. of Justice Solicitor General Style guide, published only within the last coupe of years, as I recall, suggests a variable font and an em space after a period.
Extra space after a period is still very relevant.
- Cheers

As a lawyer, and a person who produces and reads a lot of material using Word, I respectfully disagree. Two spaces in proportionally-spaced text decreases readability. This is especially true if the text is justified.

The 2014 version of the Solicitor General's Style Guide makes no mention of use of an em space or two spaces. That guide is still set for use of monospaced fonts. http://www.justice.gov/sites/default/files/osg/legacy/2014/04/21/osg-citation-manual-2014.pdf.

Like underlining instead of use of Italics, the extra space after some punctuation is a holdover from use of typewriters. I never use underlining when citing cases or authorities, I use Italics.

Note, you will want to also search and replace for spaces following colons and question marks.