Interested in Language
It seems to me that this expression comes from an ad. Here is some more context.
Fantastic Fountain (title) - it is about the Font MÓgica in Barcelona
An expectant crowd gathers and, suddenly, a strange and colorful spectacle takes place on the terraces below.
La Font MÓgica is so corny it's good.
Please, give me some hints about the underlying idea!
It is an interesting reversion of concept - that something is so bad that it can be regarded as good. In this case, the presentation is lacking originality but at the same time it catches the attention.