You also miss the message if you take them as strictly symbolic. They are both.
BTW you know there were no miles in that day so it can’t be 150 miles.
It was 12,000 furlongs. The number 12 is significant but the number 150 is not.
Rev 21:16 And the city lieth foursquare, and the length is as large as the breadth: and he measured the city with the reed, twelve thousand furlongs. The length and the breadth and the height of it are equal.