You don't have to be certified to install it, but you probably have to be licensed as an EC or at least a limited master. That part depends upon your jurisdiction.
Certification means that you possess the proper tooling and test equipment to install these systems per the manufacturer's specifications and TIA/EIA standards. Many customers in a commercial environment are going to expect a printed certification report of the installation. The physical part is fairly straight-forward, but the tooling and test equipment is expensive. Rest assured that when a cable run doesn't work, it is going to be your fault until you prove otherwise. Without the proper equipment, you'll find yourself behind the eight ball more times than you'll care to mention.
If you think that nuisance tripping of an AFCI or GFCI is a headache, wait until there's an IT guy swearing that your wiring doesn't work.
Certification isn't mandatory anywhere; it is a customer mandate that they'll have to pay for if they insist upon it. Just be careful in competitive bidding because the other bids may include certification where yours doesn't or vice-versa.
"But the guy at Home Depot said it would work."