I'd like to take your question "Is it really a good trade off?" and toss out an example set of numbers to summarize it.
Let's say there are 250 business days in a year. Operations run from 8am until 6pm, not counting after-hours processing and maintenance.
Revenue is $100 million. Gross profit percentage is 20%.
This gives per hour revenue of $40,000, per hour profit is $8,000.
A day of lost revenue is $400,000, or a loss of $80,000 of profit opportunity (assuming that opportunity costs are not recoverable).
My own calculations for my department are somewhat similar, except I've also included the additional benefit my employees bring in for the work they do when they aren't working on maintaining/improving uptime. Avoiding the cloud is almost a no-brainer in our circumstances, except for very specific & limited services.