I'm not sure what 10000 points "restriction" you're referring to. The 10000 point amount being discussed here is that in the past two years, Best Western ran a promo where all stays (at least most days) during December and January only needed 10000 points. So if that repeats this year, on most of the nights when you could use the free night certificate it might only be saving you 10000 points.

If the room is available on points, it's available for a free night certificate. If it's not available on points, it's not available for a free night certificate. So a free night certificate simply saves you the number of points you would need to get that hotel that night with points.