From the article ai understand you must opt in to make this available: These suggestions — which aim to enhance and speed up your searching experience — are only enabled when you provide access to new data types.
People complain when the default is opted-in. Now someone makes something that by default is opted-out and... people still complain.
They ask that when someone uses telemetry, that would be shown upfront. When someone does that, they ask it to be disabled by default. And when we get disabled by default, where do we go? Remove the feature, ofcourse :)
Ads, privacy and telemetry is a hot cake topic on HN.
That button is actually a cheap way to support mozilla, if anyone cares.