Businesses should use open source for all the usual open sourcey reasons:
- Better quality
- Don't re-invent the wheel
- Don't expend development effort on things which aren't your main product
- Avoid supplier lockin
- Shorter time to market
- Freedom to customize software to your exact requirements rather than what Microsoft/Google think you need
Open source business fallacies:
- "Using open source will cost you less". It might, but don't assume that. You might still want to hire support.
- "The community will provide features we ask for". Not necessarily. If you want a very business specific feature you may have to add it yourself or hire someone to do that.
- "Many eyeballs make bugs shallow". Only for the very high profile projects. Often there are not many developers reading existing code unless they need to, so sometimes bugs can go unnoticed for years. The average open source project has one or two developers.