Well, to some people it matters. I am one of them. I am 52 years old and I work in an office. It's important to me that I am not perceived as looking tired and run down (and I do if I don't fix my hair which is lost most of it's lustrous color but is not really gray). I am not trying to look 25 or even 30. I just want to look my age, but look rested and pulled together. Whether people consciously are aware of it or even want to feel that way, there is a perception that older people in the workplace are not as "with it" as younger people. Right now, I'm pretty with it but I don't want people having preconceived notions about me because I might all of sudden have white/gray hair. I wish it wasn't a thing, but it is. I see it happen to men and, more so, with women.
And yes, you have a reason to be tired. I'm *not* tired but I don't want to look like I am!