I see your point, but to be honest I'd probably pay not to have to attend Christmas parties at many places I've worked at. I suspect I'm not alone in feeling like this. Point being I don't know that this is really much of a perk......
Yes, I would prefer a $100 bonus. The amount might decrease to the point that it's useless at larger companies due to economies of scale...
If so, the choice is really between "$100 worth" of partying and $65 of after-tax cash.
For that matter, do corporations pay sales tax? If not, it's more like $100 of partying vs $58 of your choice of any consumption.
(Hence why it's not always as simple as "just give me the money".)
I didn't go to the first two and only attended after that to make nice with teh boss.