Why carriers want the ability to hide the signal strength information? It appears that this feature was requested by some carriers, and Google is just obliging. A recent piece of code committed to the AOSP reveals that carriers can get this feature.
“The ability to hide the signal strength in setting based on SIM is, and by default it is set to false”
Or, they want to hide this so users can not see how their device is performing on the network, slow or fast. This change only affects the Signal strength option shown in the SIM Status in setting.
“It doesn’t affect the APIs that are used to fetch this information, meaning third party apps would still be able to show signal strength.
The signal strength shown in this menu is the actual numerical signal strength measured in dBm or asu. The lower the dBm number, the worse the device’s network signal is. This signal strength value is approximated with the 5 signal bars shown in the status bar, though obviously 5 bars doesn’t tell you exactly how bad or good your signal really is.”