There's actually a ton of business software written in Smalltalk. I think 2/3 of the world's shipping industry is controlled via Smalltalk for example. It isn't super low level like C, so I wouldn't use it for something that needs to be blazing fast. I believe Smalltalk pioneered the JIT technology that Java uses (hotspot...if I recall correctly). It isn't a silver bullet, but seems like a neat language.