I have yard stick that I divided into groups of 10 it works pretty well.

for example my foot is 25 centiyards.

It's fine if you're jumping from one unit to another (ie. inches to feet, feet to yards). But conversion from smaller to larger units require much more (unnecessary) effort.

Eg. For a 1-acre square plot of land, what is the length of its sides in feet?

208.7 by 208.7 feet. Its not hard. Found it on Google:

https://www.infoplease.com/askeds/dimensions-acre

"The acre, by the way, was originally an English unit of measurement that described the area that a yoke of oxen could plow in a day."

Okay so quickly, without google, how many gallons are there in a cubic yard?

Now for the people who know metric it's fairly trivial to calculate how many liters there are in a cubic meter. A liter is defined as being one cubic decimeter. A decimeter being one step down from a meter means for cubic measurements it's a factor 1000. one cubic meter multiplied by a thousand is 1000 cubic decimeters or, equivalently, 1000 liters.

Note how in both examples you start with nice round numbers. I havent cherry picked a starting point that ends up nicely in metric.

That's exactly my point. You shouldn't need Google to help you answer that.