"Using numbers for putting just removes all the fun, and as putting is an
art and not a science, I cannot play this game like that."
While I think there is an art to putting I also believe its a science in how you read and aim ^^. Personally, I very rarely do anything more than an "initial" eyeball of the line to get me started. After that, I no longer visually try and verify line/break.
There are just too many funky camera angles where it's almost impossible to try and track the balls break (visually) from start to finish. I find the ART comes in reading the grid, line, numbers, and finding a scientifically correct aiming point.
So do I believe putting is an Art or is about Feel? Absolutely. It takes quite a bit of time and finesse to acquire the perfect line but for me, that is arrived by properly reading (art and finesse) the Grids, Vertex, Angles, Measurements, etc. It's all about finding the art in the perfect number, sequence, etc.
But in the end i suppose quite a bit of this game is all about personal preference and interpretation. If nothing else, a quick peak at someones putting stats. 50+, 25-50, and 10-25 should be paid special attention because there's more skill needed to consistently sink putts.