People use degrees and radians to measure angles and though degree measurement is acceptable and is widely used in everyday life, it is not in the International System of Units and mathematically it is much less convenient to use than radians (as an example, think about the derivative of the sine function if the variable is measured in degrees). Since the main purpose for the course Pre-Calculus is to get the student prepared for Calculus, in which the unit "degree" is seldom used, should the measurement in degrees be avoided starting Pre-Calculus, if not at an earlier course, in the first place? In my mind the measurement in degrees is only good for elementary mathematics.
Same argument applies to the Common Logarithm (Logarithm using $10$ as the base). How useful is the Common Logarithm compared to the Natural Logarithm in calculus, or in mathematics in general?