I'm going to gadfly a few of the things that have come up here... in no particular order...
When a caddie points to a spot on the green and tells me to aim there, it only helps marginally. I have to see the putt curve in my head. So aiming at a spot isn't that helpful.
TW, as a lifelong looper just about finished with his trade, it took me more than two decades - from teen youth to my 30s - to understand and bring together the correct, particular visualization that a particular golfer needs. That starts/started from my internal process for any putt on any course which was/has been to read the putt from the cup backwards...eg. "how is the flat entry spot on the cup situated, in relation to the general slopes feeding towards it?"...once I see that, where it goes in perfectly straight, then I just build the "putt" backwards to the player...eg...how does it get to this spot
...back to this spot...back to the player...? The only thing I think I ever was really doing for a player on green reading is matching that path/arc (of spots, from cup back to player) to a mind meld of what the speed ought to be.
How do you do that; translate the subtleties that you know from 5000 samples into a speed for today's player X? For a tradesmen like me, it IS the practical magic and only green reading property worth anything...and so when I would read a putt for you, I might have indeed pointed to some spot, short, long or near the cup, but I would've told you what description of foot-speed it should've have been..."it should be slowing down to a foot here...almost out of gas here... it's got to have enough to beat this hill and 5 more feet...you've got to have the courage to roll it firmly up here, so it can swoop down to a place where it can go in..."
There are literally 101 reasons why, though sometimes a poor mans grind/hustle, I have been remarkably and uniquely enriched by my activities lo' these 42 years, and one of the last remaining of those reasons is to genuinely meld with a player, familiar or new guest stranger - on translating the aesthetics of the putting feel to any particular putt by any particular player on a golf course, no less one I know well. And that green reading, no what its objective quality, is what drew me deeper from merely golf to its architecture and all that goes into the delightful, amusing recreation that culminates on that putting green.
Last thing TW, how about putts that aren't read to a spot outside the hole, but are nuances (verbal, pointed or both) of something aimed to one small edge of the cup...like "inside right"..."right/left of center"... "right edge"? Are such indications also of little use to you...or is it just the bigger breakers you're referencing?