I don't know, the darn things are so incredibly popular. The tickets sell out for every single night weeks and weeks in advance. There's clearly a market for these events. I think its all a bit silly myself, but it's a thing now.
But in 2020, they just can't do them without an operating theme park to do them in.
We went back in the old $10 per ticket days at DCA. I remember coming home with one of those giant Disney merchandise bags completely full of candy. Heavy enough where it was easier to carry my daughter back to the hotel and put the heavier candy in the stroller. I believe we went to the first year it was at Disneyland but haven't been back since.
I will say that we thoroughly enjoyed the WDW Mickey's Christmas party thing. Unique parade and fireworks, low crowds. Definitely worth the extra money we spent especially since I'm a sucker for Christmas stuff.