I think this feature should be added, because people want it, and options are good.
Personally, I think it's unrealistic and I probably wouldn't use the feature. Not that this is all that "realistic" a space game, but this kind of thing helps with my immersion and suspension of disbelief. In the growth of a civilization, stars would be named in catalogs long before planets around that star are discovered... let alone colonized. Many of our names for the bright stars seen in Earth's sky are Arabic, named during our Middle Ages. It's only been in the last couple of years that we've been able to locate and name planets in other solar systems. It makes sense to me that a colony expedition would want to rename a planet (there are some great sci-fi novel examples, like "We Made It"), but the star name would already exist in a very old catalog by the time your ship arrived, and you wouldn't arbitrarily rename the star.
Well, that's my thinking anyway, and I'm happy as long as the star names in the game aren't totally stupid. I still think the option should be there, for people who want this.