hm good question. I expect most people would say it isn't worth it.
I would say that, until you came back and told me that you are driving speakers with these that have a significant amount invested in the crossover. Let's say approximately the same cost as the drivers themselves. That pretty much rules out most commercial speakers.... and after this, you tried to convince me that it makes sense to spend money in this zobel, because after all, it serves the same function as the zobels you integrated into each driver in the crossover (again, something that isn't always done to start with, zobels before the driver that is)....
... then I'd just ask why the heck are you using a beta22 to drive speakers of that implied caliber...