Even though there isn't usually any formal training required to be a front desk agent, the job is a very important one.
When I stay at a hotel the first person I usually interact with is the front desk agent. This can set the tone for the entire stay.
When they are friendly and knowledgeable, I feel much better about staying there. I am greeted by someone who is not very friendly or lets the stress affect how they interact with their guests, I wonder if I should have gone somewhere else.
Not only do they need to have good communication skills, but also be able to handle multiple things at once. During the busy times when many things happen at the same time, they need to stay calm and focused on helping one person at a time.