Bitcoin, being the first and the most successful cryptocurrency,
I think there were already a few experimental digital currencies in the past predating Bitcoin which are built using cryptography. So Bitcoin might not really be the first cryptocurrency. I guess it is the first decentralized cryptocurrency though. And the most successful definitely.
Conclusion
Bitcoin is money, the first successful decentralized digital currency, which was created as an alternative to centralized fiats and also altenative to money that are vulnerable to physical thefts, thereby, fulfilling what early days money can not fulfill.
The problem is that with a digital currency resistant to physical theft, the thieves and robbers themselves have also evolved. They don't do the stealing inside houses or cars, on the streets, etc anymore. They do it online so Bitcoin is still susceptible to stealing even if it doesn't have a physical version.
It is almost impossible to imagine a thief-resistant currency.