Bitcoin is divisible into 100,000,000 Satoshis. Like cents to a dollar. Satoshis are actually the real, native, unit of the software protocol. It’s a human convention to use the nomenclature of Bitcoin to represent one hundred million Sats. To divide it further requires extensions and second layers which are viable to further subdivide Satoshis into Milisatoshis. This creates an economic space of 42 Quadrillion is still not the practical limit of what can be done. So, the only real flaw is your personal balance of Bitcoin isn’t enough digits.