“Rates in Europe are lower.“ And vary by country and city. E.g. London rates are high for Europe but less than NYC. But Berlin is “low” rates. I’d say Paris is in between the two. Also availability varies by city too, much like in the USA but much better geographic coverage. Hunqz will give you a good idea if you just explore in it.
“Different websites”. If you use RM in Europe you’ll be paying higher (think US rates or close or it) versus Hunqz or Sleepyboy.