The Importance of Instant Feedback in Analytics
In the past, prior to the current world of web and mobile development, feedback was a closed loop between the developer and the application. Often aided by tests or a compiler, desktop developers could spot issues and follow trails to solve problems without worrying about end users seeing the flaws or getting caught in a bad deploy. There were no deploys, unless you consider pushing a new version out on disc or CD a deploy.
As the world moved to web-based software and mobile software, new components came into play including cloud, containers, test-driven development, and constant iterative deployments. All these led to a new need to monitor systems far beyond the single machine with operating ecosystems prior to the web revolution.