Why do they need flight attendants? The passenger preparation for the flight should be enough. This is how you eat, this is where everything is, this is how you go to the bathroom. This is your space suit and this is what not to touch while in it. Here is the escape pod which you will enter that of course will not save you, however you will have a great view of space while you run out of oxygen.
Not much more to it than that. For each flight, someone from the flight crew will be the representative to the passengers, strictly for consistency.
The space station has had space tourists and there was no cocktail waitress/receptionist/nurse/sales lady on board.