What does "having a UI that doesn't suck" to do with using native controls? When I look at the top 20 paid apps (germany), 13 of them don't use a single native

What does "having a UI that doesn't suck" to do with using native controls? When I look at the top 20 paid apps (germany), 13 of them don't use a single native control (most of them being games). Most sucking applications in the App Store suck even though they are using native controls.