Generally speaking, currently, Malbolge is a joke language. Therefore, it's not very efficient, nor easy to write.
First of all, like all esoteric languages, it's a really good exercise for your brain! If Malbolge was Go of programming, Brainfuck would be chess, and Assembly would be checkers.
Malbolge is really simple! It won't take long to learn it.
There were attempts to use Malbolge in a few real world cases, including encryption! Just think what if some critical encryption algo would be implemented in Malbolge, and it would be very fast because of it's simplicity - it would take long, long time to discover how it's implemented.
Finally, Malbolge is not language that machines can eaisly generate, therefore it's really secure language. Imagine writing Malbolge program displaying some kind header (copyright, program name, etc.). No one probably wouldn't even attempt to touch the code!
There are a few Malbolge hackmes, that weren't solved to this day!