No you do not.
The standard Big Ben can lock to analog video. NTSC or PAL and all the usual sample rates and pull up/downs.
The X-Video option gives the following extra functionality.
Ability to act as a video clock generator.
Ability to act as video slave (like a standard Big Ben) but whereby the video outputs are genlocked (cleaned up/regenerated) versions. The X-Video card will maintain the color-phase and field information through “Genlocking”, while simultaneously stripping the original signal from its pixel information.
When connecting word clock cables, it is essential that the receiving device be terminated at the word clock input. If word clock connections are chained (not recommended but possible with un-terminated inputs), a termination plug should be connected to the word clock input of the last device in the chain. The WCOUT/TERMINATION LEDs indicate whether each word clock output is under-terminated, over-terminated or properly terminated. For more information on the subject of word clock termination, please see the document Big Ben Termination: How and Why