Since Tails 5.8 (December 2022), your data corresponding to each feature of the Persistent Storage is stored to the USB stick immediately. You don't have to restart Tails anymore after enabling a new feature.
For example, when you enable the Tor Browser Bookmarks feature of the Persistent Storage, your current bookmarks are saved in the Persistent Storage immediately.
When the Welcome Screen feature is turned on, the settings from the [[Welcome Screen|doc/first_steps/welcome_screen]] are saved in the Persistent Storage: language, keyboard, and additional settings.
When the Tor Bridge feature is turned on, the last [[Tor bridge|doc/anonymous_internet/tor]] that you used to connect to Tor successfully is saved in the Persistent Storage.
When the Tor Browser Bookmarks feature is turned on, changes to the bookmarks in [[*Tor Browser*|doc/anonymous_internet/Tor_Browser]] are saved in the Persistent Storage.