Yes, I've tried it out on my own retail lot and you can use both the styling chair and stand. As the owner you can go in and ask other sims if they'd like a makeover and as a customer you can ask anyone really but for immersion purposes ask the employees and they'll cycle you through 3 randomly generated looks. You can cancel the interaction if you find a look you like or let the interaction play through and you sims will end up back in their original look.
Asking to style or be styled isn't a guaranteed yes as other sims may tell you no. This depends on their relationship with your sim and whether they are in a good mood.
There is also no autonomy to tell your sims or other sims to get styled this is most likely due to the fact that there are no official stylist sims to man the station and since it was a retail lot the turning is set so sims are more focused on browsing the store and shopping then getting styled.
Overall though I do like having these items in my shops since they really make them feel more complete. They'll mostly be for story telling purposes and immersion however but it can be fun seeing your sims get styled and from what I've seen the generated outfits are more put together then the townie outfits. Also you can ask to be styled by outfit category so everyday, formal, party, etc. So you can tell a story of a sim going to a salon/stylist for a date or event.
