It's better not to cover all the cake with chocolate because it will be difficult to cit it. It's better to make an icing - 50 g chocolate + 2 tbsp butter + 2 tbsp sour cream + 2 tbsp sugar). Heat until sugar dissolves.

In my opinion chocolate makes cake more appetizing, that's why I often use it and recommend you to use your imagination and make different patterns to decorate your cakes.