The idea is that sometimes we need a string because of how the system works but it should not be translatable.
Sometimes we need a string but we don't want to hard code it in the code, or it is displayed in a place where we need it as a @String,
<string id="version" translatable="false">1.2.3</string>
Sometimes it just makes no sense to translate it:
<string id="unit" translatable="false">km</string>
<string id="empty" translatable="false"></string>
<resources>
<fitContributions>
<fitField id="0"
...
unitLabel="@Strings.fitUnit"/>
<!-- this is a string field that displays a string saved from the settings, but it has no unit -->
<fitField id="1"
...
dataLabel="@Strings.name"
unitLabel="@Strings.empty"/>
