What a computer does well:

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!