Rare coins that are now valued as artefacts were once monetary assets. So I'm not sure that this distinction is meaningful.
BTC's value now could come from it acting as a store of value for example. Or its value could come from the novelty aspect. Or that it facilitates online gambling (leveraged bets on crypto exchanges) in countries where such activity is heavily restricted. BTC's value in the future could come from it being a historical artefact. Lots of subjective reasons investors may have for holding it (just like they hold a piece of art) beyond its use as a currency.
Well the value of any asset depends on the value that people assign to it -- it's all subjective if you really get in it.
However, I wouldn't accept bitcoin as a method of payment because I'm not confident that people will agree to a completely different value in a very short time frame. Meaning will it be 50k next week? 5k? Who knows!
BTC's value now could come from it acting as a store of value for example. Or its value could come from the novelty aspect. Or that it facilitates online gambling (leveraged bets on crypto exchanges) in countries where such activity is heavily restricted. BTC's value in the future could come from it being a historical artefact. Lots of subjective reasons investors may have for holding it (just like they hold a piece of art) beyond its use as a currency.