How does this thing work?

Something I am greatly looking forward to is carrying Adeline around in one of these bad boys. I haven’t actually carried a baby in one yet, but I have tried a couple on (as you may have already noticed). They do seem to be pretty easy to use. There are a few different kinds on the market, baby bjorn is probably the most popular. This petunia picklebottom seems to be a luxurious ride for the little one, and is oh so stylish. I'm starting to look at these as my wife would a handbag, but I only need one (well, maybe two). Do I need one to match this outfit? One to match this hat? I may be losing sight of the point of these things. But, I guess a Daddy needs some retail therapy too.