I think the primary reason that such methods are not used much in practice is memory and computational cost: each function evaluation is expensive and you need to solve a very large system at every iteration.
Also to reply to a sibling comment, you can add momentum and step length adjustments to second-order methods in much the same way as in steepest-descent to help escape saddles. The only difference is how the descent direction is chosen for the optimization.
I think the primary reason that such methods are not used much in practice is memory and computational cost: each function evaluation is expensive and you need to solve a very large system at every iteration.
Also to reply to a sibling comment, you can add momentum and step length adjustments to second-order methods in much the same way as in steepest-descent to help escape saddles. The only difference is how the descent direction is chosen for the optimization.