A Facilitation Kit is definitely not required. In fact, if your course objectives are very specific to your business or industry, a kit may not be worth it. Even then, though, the kit's pre-built course materials are freely customizable and may be a great starting point.
Another advantage of the kits is the videos. Having people model the styles in context-specific situations is the often best way for learners to understand the differences in styles. While the kits are not inexpensive, creating a similar set of professional videos would cost many times the price of the kit.