If you're designing a new airliner then yeah, you can't screw up, and you end up taking years to deploy.
In the HFT world, you may have only days, or sometimes hours, to deploy. Yes you still write tests, and a bazillion safety checks when you deploy, but if you manage your risk down to zero then this is definitely not the most profitable way to go.
In the HFT world, you may have only days, or sometimes hours, to deploy. Yes you still write tests, and a bazillion safety checks when you deploy, but if you manage your risk down to zero then this is definitely not the most profitable way to go.