High Sierra and local TimeMachine backups

I was wondering where some of my disk space was going, and realized that macOS HighSierra will make local TimeMachine backups as needed, and while disk space is available. This might be cool in some cases, and you can see (and delete) these snapshots with 

$ tmutil listlocalsnapshotdates /Volumes/com.apple.TimeMachine.localsnapshots
2017-11-29-134430
2017-11-29-144409
2017-11-29-154648

$ tmutil deletelocalsnapshots 2017-11-29-134430