You are incorrect. The supply of bitcoin is limited. Whether you express that limited supply as units of bitcoin or units of satoshi does not change that the supply will never exceed that amount.

Doing a unit conversion doesn't change anything. The limited supply argument is not implying that you won't be able to own fractional bitcoins, it's arguing that the amount of bitcoin you do own with always be a fixed proportion of the total possible supply (in reality it's proportion will grow as people lose access to their keys) so it won't get devalued by the total possible supply increasing. Remember, value is relative to the supply. Looking at your bitcoin in terms of satoshis doesn't change it's value.