Because SolusOS is now based on Debian. But that gives lot of troubles, need lot of fixing, etc. So that is why the creator of SolusOS is looking for something different. And that is PISI. And b.t.w. he also work for LinuxMint before, so he really got knowledge. And then all we have todo is building packages, so both can use them. SolusOS and Anka.
OK, makes sense (although I used to think that .deb packages do not give as much trouble as suggested here), it IS a very interesting development. However I am a bit reluctant as SolusOS concerns because so much seems to be dependent on just one excellent person? Or is that a statement you regard as too simplifed?