Earlier quoted context omitted.
Also worth pointing out that LLPSI is essentially Hans Ørberg's life's work. It's been adjusted and fine-tuned for decades, and it really shows. While at a surface level it looks fairly simple, it is no small task to repeat the process with another language.
Giuseppi Peano tried to get people to learn an "unconjugated latin" by writing mathematics in it. eg https://archive.org/details/formulairedemat04peangoog/page/n... (mini rationale https://archive.org/details/formulairedemat04peangoog/page/n... ) Maybe set theory wasn't the best way of introducing a conlang, but I have to take my hat off for the weird flex.
Funny, it's a bit like listening to Portugese when you've got a basic understanding of Latin. A lot of the pieces are there but they're all a bit off kilter.