Hi, Thekla;
I agree that these do work, but they are limited in how long your wood can be cut, and, as stated, they are SLOW.
Two years ago, I badly broke my right wrist. Chopping wood was not part of the program.
The problem was that we only burn wood, and locating a teen willing to work was a pipe dream...
I took matters into my own (one) hand and went with a low-cost electric splitter.
Of course, it had so many safety features as to be unusable by a one-armed rocket scientist, so I had to make unauthorized modifications.
After removing every safety modification, I created a fully functional one-handed splitter!
https://permies.com/t/219033/electric-wood-splitter-modifications
Cost was apx. $300 plus the foot switch.