^^^
The way i see it is that the chances of you finding that one person you really click with, and having that person feel the same about you are pretty minimal. By displaying interest in a few people and just seeing what happens on each front allows for some flexibility when they don't work out, which, lets face it, is more often than not. So yes, it is like a safety net.
If you have really fallen for someone then by all means pursue them and only them but if you have an interest in someone, and you would like to get to know them better that shouldn't exclude you from displaying interest in anyone else - unless something further manifests with one of them. If that happens then appropriate choices should be made.
Adikkal