Another problem is that (in my experience) the few times that I have seen someone attempting to marshall me at a scene they have invariably chosen the wrong place. It has either been too close to an obstruction, the surface wasn't suitable, they were seriously underestimating the downwash and were standing far too close or my crewman was giving me totally different instructions. Or on one memorable occasion they had marked the only suitable landing site with a large sheet held down by 4 small rocks.
So I ended up landing in a different spot and the helpful marshaller gets annoyed and thinks that I intentionally ignored the signals so I am an ignorant prick who has made him look very silly in front of his colleagues. So I have to go up and explain why I chose not to do what he wanted.
By all means give as much information to the pilot as possible over the radio then if you think you have found a suitable place tell him that you will stand there and indicate it. Raise your arms above your head and lower them to indicate the landing area and direction then get out of the way and let the crew do their thing.
If the pilot then doesn't don't thank you for doing that - he very probably is an ignorant prick.