TBH, it doesn't look "easy" at all. Plus, why re-inventing the wheel and create yet another containerization system?
Because that is how we make progress. Try different approaches, learn and evolve the ecosystem. That is how we got usable containers in the first place, it's not a new idea and variants have been around for decades. But only now we've seen it evolve in to something usable.
At least they are trying to solve problems. It might not be the best/right solution, hell it might not be an improvement, but if we don't try, we will never learn.
If anything, Docker just made containers trendy (they gave more talks at more conversations, etc) when before it was seen as a niche toy compared to virtualisation which few had heard of and fewer had bothered to look into. However being trendy doesn’t mean better nor easier to use.