How about moving gigabytes of data that underlie the application? The egress cost is not that low. The access latency is utterly important. Raw computing power on small amounts of data has a limited applicability.
It's also a reason putting things on the cloud is a fools errand. If you can be held hostage by a provider, you made a business mistake by going there in the first place.
Egress is not that expensive. You use it to serve the customers, in the end.
But it's (still) too expensive to allow migration between cloud providers e.g. on hourly, or even daily, basis. That is, it prevents the consumers from realizing the benefits of short-lived spot prices.
