My only real objection I guess, and the reason I don't carry change of any sort, is because it's constantly falling out of my pockets. I'm rather tall, so many seating positions put my knees higher than my waist, which I think contributes to that.

Further, since I don't have enough pockets to have a dedicated change pocket, it's always getting caught up in my keys and/or pocket knife.

Nobody really gave us training on this stuff, do other countries use a coin purse or some such?

Lastly, they're just comparatively heavy.

I just carry cash around in either a clip or a "front pocket wallet" I think they're called, and it seems more convenient all around.