Thanks for the balanced reply! Yes you're right, I'm only using lossless and lossy as a metaphor here, because of course, any translation will lose information. Even speaking your native tongue with another fluent speaker will lose information because the meaning is interpreted.

However, I'd say that well-developed languages (which for me means having many hyper-specific words and a diverse vocab available) allows interpretation to be more precise and functionally allow communication to happen. With Toki Pona I have the sense that a lot more is lost, and we end up interpreting broad strokes of the original meaning. This isn't bad, it's just different. Poetic if you like.