1. Because you have many different keywords and services that you want your business to show up for, right? Do a video on each service that you want to be found for, at a bare minimum. Really you should have at least 30 videos so you show up many times for each keyword. Not only that, but your videos are a great opportunity to answer the most common questions that people have about your services like who, what, where, when and the big one, WHY or HOW.
2. Videos rank MUCH EASIER so your video could be on page #1 on YouTube and/or Google in as little as one day!
3. You create videos, post them and rank them once, but they bring you business for forever!