Runs trains automatically
Runs as many trains as a layout will support, which might be impossible without a large number of operators
Runs trains at realistic speeds, including acceleration and deceleration
Changes points and signals
Sets routes through junctions
Manages extra DCC functionality, including lights and sounds
Manages your layout extremely safely, avoiding collisions and protecting your valuable trains
What a computer may not do well:
Control of shunting, including uncoupling and other fine movements ...
Some operators have told us that they have been able to use computer control in this way, but it tends to be something that is set up for a specific function on a specific piece of track, rather than an action that fits every situation. In other words, limited or specific use may work, but on the whole fine movements are better achieved by a human operator. At least this gives them something to do while the computer is running everything else!