I think there are three types of Cape Horn passages.
1) You arrive at Cape Horn from the west (New Zealand effectively) and have to pass the Horn in whatever conditions happen to be there at the time - call this the Volvo Ocean Race case.
2) You arrive at CH from the east. This is like 1) except you have the added problem of foul currents and prevailing winds - call this the HMS Bounty case - they could not make it and headed to Tahiti east around. This is obviously less of a problem for a modern yacht than a square-rigged, 18th century transport ship.
3) You approach CH from the channels of Tierra del Fuego. The immense advantage here is that you can wait for the right weather in a reasonably protected spot and then pop out to round the Horn - call this the Sequitur case.
I am not suggesting that Sequitur's achievement is not significant, not just for actually rounding and heading to the Falklands, but just in getting to the southern tip of South America. It it not too bad as far as Easter Island, but when we were at Easter there was another Canadian boat heading to Chile to wait for the next season to go south. They had two serious gales on the way to Valdivia. From there on you are into amazing cruising grounds, but you are pretty much on your own - no 'Boat Chile' to call so you better have great ground tackle and not know what you are doing.
My sense would be that you take on this trip because you want the cruising experience involved getting to Easter Island, along the coast of Chile and in the southern channels. Getting the picture of Cape Horn would just be a plus.
Finished the circumnavigation in early February in Grenada. Have to work on a book project for the next several months so the boat will be waiting for next year.