This is the equivalent of two full time. The results are available at once, without waiting. As soon as someone has done a test, you can see whether they have passed or failed. If you are using the test to recruit or authorize someone to do a job, then speedy results mean the job is done faster. And if you are using the test to spot failure, then you spot it faster.
Computers are objective.
They don't make mistakes. And they don't suffer from personal bias. It's very important to get the questions right, and to set up the marking criteria, but once you've done this, the computer will do the marking with precise accuracy. It's easy to get the computer to give helpful feedback to people taking tests. As well as simply working out a score, you can give diagnostic information to people about which topics they are strong or weak on, or why their answer to a question was wrong.