but bitcoin is not just creating a coin thats passed to a decendant ..
bitcoin has other functions.
it actually also has an underlying COST.(mining cost)
check hal finneys post about price discovery.
One reason price might follow difficulty is that mining should not be too profitable (because nothing should be too profitable, the world doesn't leave free money lying around). Therefore the price of Bitcoins can't rise too much above the cost of mining (counting equipment depreciation among the costs of course). The cost of mining is proportional to the difficulty (approximately). Therefore we might expect to see price proportional to difficulty.
users in 2010 gave it a price because of cost them $0.07 to mine 1 btc. and those that didnt want to burn their cpu/gpu for an hour or so per coin would instead just buy it instantly to save time and stress, and usually pay a premium for instant access to coin without the stress/burn cost.
it had a value..
functionally: it has utility. too
you can do things with bitcoin. which you cant with your signature chain
your 'pass a love letter' has no underlying value cost and also has no ownership of the original item you say it does
because the descendants dont get the private key (the underlying asset you pretend they get to own)