I can understand how some of the unique aspects of most places to stay in the Cinque can result in very bad reviews of a place for visitors that did not research previous reviews much.
While not saying the OP does not have a right to complain, had they read up on the place via online reviews I think there dissatisfaction would have been greatly lessened. A guidebook does not go into as much detail as you can find reading dozens of reviews, space just does not permit.
Is a good lesson for others though.
For your friends in Sept. , they need to get moving. Places like the Hotel Villa Steno are most likely fully booked for the month at this time.
I think as a blanket statement you can say outside of Monterosso in the other 4 towns there really are no hotels by the definition we think of. The places to stay would either be called B&B's or Apartments/Rooms for Rent.
They may or may not serve breakfast.
In most cases in these 4 towns if your place has a nice view you will have many, many steps often with narrow areas that make luggage a major hassle. This is the norm, there are some exceptions but generally this is the case and makes it very important to read reviews thoroughly as the walk when cumbersome is typically mentioned or if easy it is often mentioned by folks knowledgeable about the area.
Many tourists prioritize a view and/or want a small balcony and often don't realize the inconvenience to get up high that it means. In Vernazza this seems especially true.
Cash as payment is the case in probably 90% of the listings I have seen, the Cinque Terre seems very behind compared to the most areas of Italy that tourists frequent in terms of widely accepting credit cards.
I was surprised that it seems like Air BNB listings are often the only way to avoid paying cash at hotel for a booking since AirBNB requires the room be paid through their system.
There is also a room nightly tax to be paid in cash, which is true throughout the country not just in the Cinque Terre, rates vary but usually a minor amount.