Once a few clever souls realised they could increase their visibility by adding hidden words, they started appearing everywhere almost completely ruining any chance you had of finding something you want or need by searching due to all the false positives.
I know this arms race is still ongoing, but it's interesting to see back where we've been.
- that's just an insane thing to suggest, that would exclude much of the world's poetry, lyrics (I'm looking at you Icona Pop), code, etc etc etc. What does it even mean "to parse" in this context.
"it's trivial to deduce that the text doesn't display" - for that example it might be, but in general it's anything but trivial.
In a similar vein, "invisible to user" text may get cross referenced with "visible to bot" text and if there's a discrepancy, that may count against your rank.