> I would certainly have to think a lot harder all the time if I were spending stocks or tiny pieces of land.

You said it yourself: people don't hold cash. They sell their assets before buying something with cash. And it doesn't seem to prevent them from spending. With Bitcoin, it would be the same thing except the whole "sell your assets before you buy" process could be skipped.

Of course I oversimplified a lot here. People don't literally sell their stocks/real estate before they buy something. But I'm sure they would if those assets allowed them to.