but... why we should invest with BTC not GB? How GB will be backed in this way?
If i send 100$ (BTC) to you, i will get GB (which probably i will dump) and gold bar (which will be sold)
I don't get the point
Whatever you choose to do with your investment will be your decision.
GB are backed up with gold, investors's btc will be used to backed up GB price on exchanges and for further development. Thats why they are investors. They invest in something that they believe that will have a great success in the future.
GoldBlocks prefer real investors, not dumpers, however it is free market.