I spent 7 years in physics, and physicists often (most of the time, even, in my sub-field) spoke in field-specific lengths.

"The pulse is 1.6 plasma wavelengths long", "the shock front is on the order of 2 laser wavelengths thick", etc

SI dimensions (again, in my sub-field) were treated more as a manufacturing spec for experimental equipment than as a convenient way to discuss phenomena or a good way to communicate the size of something with someone else in the field.