couldn't conceivable sell and replicate their position in actual Maidsafe without moving the price considerably
Didn't get that part.
Meh I'm sure economics guys can explain it better but to me it works like this -
If you have a BitBTC then in theory you should be able to sell it and buy yourself a real BTC if you want for not too much loss whenever you want to sell your BitBTC because BitBTC tracks & holds the value of BTC.
However if a BitAsset market gets too big it can misprice the market it's mirroring because the price for that good is set somewhere else.
So for example Maidsafe's price is determined by how much people are willing to pay for an actual Maidsafe coin.
If we made BitMaidsafe it would track the price of a Maidsafe coin but it wouldn't set it.
So if there was say $7 million of BitMaidsafe in existence & $10 million of actual MaidSafe then
-it underprices Maidsafe because if the money invested in BitMaidsafe was invested in Maidsafe itself the price would be much higher &
-if even 10% of the people wanted to convert their BitMaidsafe into a real Maidsafe position over a short period or in an emergency they couldn't do so without sending the price of Maidsafe very high in which case BitMaidsafe won't have done a good job of storing Maidsafe value in some instances.
Some commodity markets have a worse problem in that they wag the dog & set the price of the underlying market, so gold for example is really mispriced and there will be a huge upswing in the gold price if a small % of people who hold a paper gold position try to replicate that in real gold.