We're not talking science, we're talking public use.
Stars have catalogue numbers - there aren't enough names in all the languages in the world.
Planets, logically, should be numbered in sequence around their star, not named.
The problem is with the lay public, for whom the Planets are occasionally relevant (usually when they read their horoscope, unfortunately, but some are interested in them astronomically or geologically).
Each day of the week has its own name, each month has its own name, but each day of the year does NOT have a unique name - only special days like holidays, and the markers of New Year, midsummer, solstices, equinoxes etc.
365.25 is too many days to name.