People believe in Bitcoin because there is something in it that they saw and want to. For example, investors believe in Bitcoin and invest in it because they saw it's potential to grow in price while others who believe in its technology, invest in it to support it.
Then it can LITERALLY apply to anything...
Yes, just go build something that is a decentralized digital currency, with no 3rd party required to transfer payments between the owners of the new currency.
Then have people
value it at $0 - $1 for a couple years.
Watch a couple years later when it bounces between
$1-$10 in value around the world.
Then when it gets in the
$10 - $100 range, you just have to get over that hump before your new "currency" appears to have some valid reason to actually exist.
And if you can get over the
$100 - $1000 value area for this new
digital currency that
anyone in the world can own or use, you will have recreated
what Bitcoin did. Congratulations.