Maybe you're right and there is some overlap in the meaning of the points on this list. Suffice it to say that RPerl is about speed and maintaining backward compatibility with existing Perl 5 and XS. Kurila is not.
Does that help?
Re^12: Perl 5 Optimizing Compiler, Part 10: Kickstarter & Performance Benchmarks
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these are very different approaches, but there is some thing that makes these 2 very similar, ...
there is one point (at least) where kurila had much more chances compared to rperl: it was lead by a very smart leader, who 1) deeply understood p5 internals, and 2) when asked for something provided quite thoughtful answers, instead of stuffing some list with repeated and wrong entries, for the only sake to make it bigger,
In a sence, we have a score 2:1, kurila currently wins.
It could be that the score will change in a future, but right now I do not see something that will really make rperl win this (imaginary) battle....