It is absolutely not okay that a dog sleeps in his owner's bed! That is sick and twisted!
A cat only -like mine- should be allowed to sleep in the bed of her/his human!
If you are fine with your dog/cat in your bed, it's all okay...I would say.
Yes, there will be hair. Yes, there can be dirt.
But hey, it's nothing a washing machine couldn't handle.
And who am I that I would wake my tomcat while he looks so cute while sleeping

And he has his own little blanket where he always sleeps, so there is not so much cat hair in my bed
[Edit]
Just don't forget that your dog is a dog and a cat is a cat and not a human.