I use the MBTA buses sometimes to get from my house to the nearest train stop after which I make a transfer to another bus. A real time map of the bus locations would be 100x more valuable than just a prediction.

Same with the train - I use a website that shows the exact locations of all the MBTA trains, and I am able to accurately predict how long the train will sit outside of the Alewife station (which is infuriating BTW) based on the number of trains currently at the platform. A prediction would not be able to take into account this domain knowledge and would be completely worthless.