An interesting study was published on website of Internet Measurement Conference in 2012: Inside Dropbox: Understanding Personal Cloud Storage Services.
Authors highlighted that applications running in cloud-based systems produce most of Internet traffic.
They have monitored traffic from different places within Europe from March 24 2012 to May 5, 2012 and it turned out Dropbox generated 100GB of daily traffic, which was 1/4 of Youtube traffic.
Several facts from the article:
While Dropbox focuses on big corporations, they do not have any reason to overpay for security of small and midsize business.
Another example from 2019. An AI-related Israeli startup stored data on AWS S3 and one day their data leaked to the Internet. The company ceased to exist within one week.
Data is the new asset and there's a big race for data in the world now. The company that has data, has a better position on the market. Therefore we recommend you to learn how your data are stored: the infrastructure behind the "cloud" you are using, who has access to your data, etc, as this type of asset has special "storage conditions".