With a regular SIM card and an eSIM embedded inside a phone, users can have two separate lines using two different plans inside one device. For example, one line could be used for work calls and the second line for calls from home. However, if you’re talking to your wife and the boss calls on the office number, the call from work will go to voice mail. There also will not be a notification for the missed call. Call waiting will work if you get a second call on a line that is already in use.
T-Mobile is expected to begin supporting the eSIM for the 2018 iPhone models some time this month. Sprint will also join the club, although it is not clear when the carrier will announce this.