Imaging daily life with crypto

Something I've been wondering in private is how would daily life look using only cryptocurrency. I know there's many people out there who want this, but I was wondering what you guys think about how difficult the math would be to do in your head to pay for things.

Take bitcoin for example, at a maximum of 21 million bitcoins, which means if the entire world adopted Bitcoin the division of each bitcoin would have to be extremely small to translate the current 38 trillion in currency worldwide. Even smaller still if you correctlyassume not all bitcoins are in circulation.

Assume you get paid the current equivalent of $25/hr in current bitcoin, 0.002469, and you want to buy some pants that cost0.01185. How many hours do you have to work to afford the pants?

It's not realistic for someone to do this in their head, and this strikes me as the biggest issue for bitcoin adoption.
Also we have it pretty easy in the Western world, in Vietnam their currency is 26,000 to $1.

Anyone have any work-around to this issue?