In the old launcher, the game would autoupdate to the latest major release when launched. When the first version of the new launcher was released, they removed this feature, replacing it with a list of all versions to chose from. With the release of the latest version of the new launcher, they replaced that with a list of profiles that can be set use any specific version of minecraft, or the latest version. However, the option to update to the latest version also includes snapshots, so it is not the same thing. The way I would expect most players would want the launcher to function most of the time is just to update their minecraft to the latest major release, then launch it, and this seems to have been unintentionally removed with the new launcher.

(just to be clear, what I mean by "major release" is anything that is not a snapshot, whether or not that is what the word is supposed to mean)