I will respectfully disagree. This website doesn’t allow two spaces but I don’t normally use a proportional typeface while doing anything (writing) and think in fact that even though I’m using an older typeface, Bernhardt Roman, and my style of writing is largely ungrammatical, two spaces is more aesthetically pleasing to read than one.
I have typeset with metal type and used the above typeface — spacing is a very art sensitive matter.
If all the reading you do is on a screen, then perhaps it is appropriate but that’s not the reading I do most often.
So We can agree to disagree.