I’ve never understood that. Even if they accumulate a fair amount

"Spare change jar" might not be accurate. Many people's coins might be scattered amongst their pockets, purses, vehicles, etc, rather than in a centralized location.

I’m the exact opposite. I always try to get rid of my coins.

I suspect you are not like most people :)

I ask if they have $2 bills. I got $80 worth last time.

LOL, you might get along well with my dad. He's purchased rolls of 50 cent pieces, to similar effect.