Why use standard (index) form for small numbers?

Example 1

It makes small distances easier to understand

Standard index makes smaller distances easier to understand

The width of a human hair can be written as:

$1.7times10^-5$ m

Or

0.000017m

Which is easier to understand?

We think $1.7times10^-5$ m

Example 2

It makes currency exchange rates easier to understand

Standard index makes exchange rates for money easier to understand

The Vietnamese Dong is such a weak currency 1 Dong is worth approximately:

$£3.39times10^-5$

Or

$£0.0000339$

Which is easier to understand?

We think $£3.39times10^-5$

Example 3

It makes small masses easier to understand

Standard form makes measuring tiny things like an atom easier to complete

The mass in grams of one individual carbon atom is:

$1.994times10^-23$ g

Or

0.000,000,000,000,000,000,000,01994g

Which is easier to understand?

We think $1.994times10^-23$ g