I thought that Partwork was designed so that anyone could assemble them.
Quite right but from anecdotal evidence it doesn't always work out that way. In some cases part don't fit together properly etc. (I don't think Martin ever finished his Bismarck...)
It is a big commitment on both sides, not just the cost but is there a guarantee that publication will not cease due to low take up of the offer as Kinmel says above? There doesn't appear to b any guarantee in the advertising.
From a practical viewpoint I would be wary of a model which is 1.3m in length when no single piece can exceed the dimensions of a magazine page. To me this suggests rigidity issues as every hull piece must be a perfect fit with the others and to achieve this may require quite a bit of 'over engineering' and hence extra manufacturing cost at the very least.
Obviously it depends on what the purchaser wants to get out of the model, but if you just want a superb scale model of Titanic where the parts are guaranteed to fit together then you could buy the Trumpeter kit for a quarter of the cost and there are lots of extra detailing options available if you want to enhance it further.
The Mantua 1:200 Titanic in it's static display version costs around £820 and is constructed using more conventional modelling construction methods which I suspect most modellers would find more satisfying than the Hachette assembly method.
Both the latter versions can be constructed in under the almost 3 years it will take for the part work to run.
Food for thought anyway.
Colin