Why does MP spike every time the LEAPS come into play?

If we take anything past $127.50 at face value (you can't buy those), the max pain goes all the way up to $180.

What happens when these strike prices go away ("forever") after this week?

I assume they're used as locates in some regard, but what does Citadel lose here?

Most of these odd strikes seem to have been first purchased between 11/7/21 and 11/14/21, any significance I'm missing?