Personally I prefer replacing the text and then applying a light blur. Let them feel smart for a few seconds.
Re:A critique of Gmail's “smart replies”
by userbinator on Monday November 12, 2018 @04:00PM
(#18435763)
Yes, the first thing I noticed is the date quite clearly says 18 (why not blur the whole thing?)
There's a discussion on deblurring techniques before: https://news.ycombinator.com/item?id=4679801
[0] https://cdn-images-1.medium.com/max/2000/1*h8cIVhi7n9-vuNJ-1...
Edit: I just noticed parts of the concealed text have been "smudged" before blurred. So no risk here. Still valid as a PSA :)