We used a lot of coolant in my shop. Almost all the lathes had flood, the vertical mills had mist or flood, CNCs had flood, the saws had flood, the surface grinders.... you get the idea. It's different when the machines are used frequently and have oil skimmers running 24/7. It's also different when you have an apprentice to maintain and change the coolant. With all that, you still come home smelling of rancid coolant, which doesn't wash off easily. I won't have coolant in my home shop, even if it may have some advantages. I'd rather smell like cutting oil.