Why is the metric system of measurement convenient to use?
Because it's so much simpler and easier to use. The metric system is an improvement over the English system in three major areas:
1. There is only one unit of measurement for each physical quantity.
2. You can use multiplying prefixes to express the size of a measurement by using a multiplying prefix. For example, 1 000 m = 1 km; 0.001 m = 1 mm.
3. It is a decimal system. Fractions are expressed as decimals. This allows unit conversions without doing math — simply by shifting the decimal point.
You can find a much more comprehensive argument at