Get rid of 'store of value,' 'decentralization,' 'smart contracts' and all that's left is a ledger. Its really not that complex or special - if that's what fascinates you then you can just as easily approach the topic from the examples of traditional credit or even the history of semi-arbitrary currencies.
If your implication is that the only thing backing crypto currencies is an expectation of reciprocation then you are mistaken. The qualities you want to hand waive away, and most importantly (though often trivialized), is the inability to roll back the chain which is a function of "consensus power." Consensus power simply quantifies the cost of rolling back x blocks. Bitcoin currently has the highest cost to roll back blocks and therefore the most assurance.
If your implication is that the only thing backing crypto currencies is an expectation of reciprocation then you are mistaken. The qualities you want to hand waive away, and most importantly (though often trivialized), is the inability to roll back the chain which is a function of "consensus power." Consensus power simply quantifies the cost of rolling back x blocks. Bitcoin currently has the highest cost to roll back blocks and therefore the most assurance.