The usual quip because Go has no Templates/Generics, so you have to sacrifice type safety all the time by casting to and from Interface{}.
One of the philosophies behind Go is to keep the language extra simple.
See "less is exponentially more".
The same way some electric bikes are restricted to a given speed to keep their user safe. Some people call it "crippled", while some other call it "simple and safe to use".
Keeping a language simple just punts complexity from the language to the implementation that uses that language. This is all the same problems that C has and Go chose to for some reason copy this poor philosophy. It's like Go designers decided most programmers are too dumb to understand complex languages.
The beauty of programming language design is not building the most complex edifice like Scala or making the language unacceptably crippled like Go - but giving the programmer the ability to represent complex ideas elegantly and safely. Rust really shines in that regard.
i'm fairly ignorant on the various differences but my general feeling was that Go is quite useful?