While I tend to use the verbal shortcut, your way is much less likely to be misinterpreted.
"Set the power to point three" sounds the same orally as "Set the power two point three"
The zero makes it unambiguous.
"Set the power to point three" sounds the same orally as "Set the power two point three"
The zero makes it unambiguous.
Except in deliberate word-by-word pronunciation, "one two three" and "one to three" sound different in native US English.