Levy made some excellent points. If you cannot afford to pay for training, you should not do so. Pay the phone bill instead. And, conversely, if you buy them, but don't use them, it is a waste of money.
I liked the point he made that a lot of training is not applicable to positions one reaches in games. I find my self in a King and pawn endgame a lot. Therefore I studied that endgame and use it in probably 80% of my games. On the otherhand, I have not spent any time studying how to mate with two Bishops against a King. I have played thousands of games in my life and never ended up with that endgame. Even if I learned how to mate with two Bishops against a King, I would probably forget it by the time I eventually find myself in that position. Learning that information would be a waste of time as it would not be applicable to my game.
I know they're very high-level lines, and a lot of great analysis, but they also cost a boatload of money (especially with the video 🥴), and a lot of the lines (at least from my experience), it's very unlikely they'll show up OTB. I'd also wonder if it's more effective to use move-trainer, or just input the course into chessbase or something equivalent?
Obviously I'm sure different people have different experiences. Also, I thought of that after watching the below Gothamchess video