Question about mist and CE and buying stuff

I went to buy a trinket slot earlier. Just before I bought it, I noticed my mist had recovered from 0 to 1.
After buying it, and a few other things, my list was at 0 again. So it got me wondering...
When is mist used and not used?
I know it's used for elevators and revives, as I've used it for that.
I know it's used for crafting, as I've done that too.
I know it's NOT used for market trades.
So when else is it and is it not used?

Read the wiki page "Energy". It explains that in any transaction involving energy, mist energy is used before crystal energy. So if you buy a trinket slot upgrade from Kozma for 150 energy, and you have 1 ME, then you spend 1 ME and 149 CE. I have verified this many times.

So the only thing mist is not used for is market trades?

What's a "market trade"? You mean Auction House? ME can't be used there, because it's all crowns, right? You mean trading with another player? No, you can't trade ME to another player. You mean Energy Depot, where we sell energy to each other? No, ME cannot be sold there, because that is just trading with another player in disguise. You mean buying something from a vendor using energy? Yes, ME is used for that.

Mist energy will be used BEFORE Crystal Energy. Mist cannot be traded to other players. Any questions? Don't hesitate to ask. :D
-Midge

You can however tab someone else down an elevator and they can repay you with something else. So not directly traded.

You guys are not aware of the market?!

Bopp already answered your question:
"You mean Energy Depot, where we sell energy to each other? No, ME cannot be sold there, because that is just trading with another player in disguise."
Mist is the main energy. Mist is probably only not used for trading and sending mails.