Why is XCTMetric's applicationLaunch metric deprecated

I just noticed that in Xcode 12 XCTOSSignpostMetric.applicationLaunch is deprecated. But I'm not seeing anywhere in the documentation that alludes to an alternative—so did Apple decide testing app launch in this manner isn't worth it?

I know MetricKit and Instruments include app launch data, so it's not like there's no way to measure this. I'm mostly curious about their reasoning since calculating the average of warm launches from the XCTestMetric sounded like the right thing to do in order to get consistent results.