Target line is not a new concept in putting

Palmer (1986) in his book “Arnold Palmer’s Complete Book of Putting,” stated (p 31):
“At this point it might be well to make another important policy decision. Are you going to (1) visualize the line to the hole and seek to direct your putt along that track? Or are you going to (2) adhere to the school of thought which holds that all putts are straight and that the best technique is to convert your assessment of the putt into a phantom hole, or target point, and start the ball at that spot? The choice is essentially a matter of temperament and what works best for the individual. As a very broad generalization, (1) stroke putters normally adopt the first method, while (2) rap putters prefer to work out a target point wide of the hole and putt straight at it. Both systems have their pluses and minuses, so it is really a question of how you "see" the putt. It is probably easier to fix the line if you have previously determined that you are going to use it like a cart path and drive your putt along it. The danger with this method is that you may be tempted to try to impart some form of swerve to the putt, by involuntarily adjusting the angle of the putter face.”
All target points “wide of the hole”, as described by Palmer, defines a target line. Dave Pelz (1994) in the article "A study of golfers' abilities to read greens" defined it more precisely as a straight line that (1) passes through the hole, and (2) is perpendicular to the ball-hole line. He also defines ‘true’ break of a successful putt as the distance of the aim point from the hole when the ball starts with ‘optimum’ speed. He used his True Roller to determine ‘true’ breaks.

Is it not a choice of ball speed v direction? Where the line has breaks the ball can be sent fast in a straight line that overpowers the break or slower off line to allow for the break. Obvious danger with the first is that a miss will take you way past.

This sounds like a glass half full v glass half empty discussion.

Visualising a line of a breaking putt to the hole or visualising straight putt to a phantom target allowing for the break read seem to be two differing views of the same practice, ultimately the ball will be started on the chosen target line at a speed considered apropos for the length of the journey...

For me there is no right or wrong in this, just go with whatever works for you...

Cheers

Trick Q: The answer is all putts are straight putts. Whether it's a straight putt for 1 foot to an intermediary target on your imagined line, or a putt equidistant to an imaginary hole, you're still trying to start the putt straight.

But Brian and Scragger make the key point: There are an infinite number of lines based on an infinite number of speeds at which the ball approaches the cup. Aggressive (fast) balls need much less break - so there's your own personal stroke and ball speeds to factor in as well.