Yes bitcoin is an integer based system but right now there is a decimal point. If there was no decimal point 1 bitcoin would be equal to what is currently called 1 satoshi. Have you read Carvalho’s BIP? Carvalho’s proposal shifts the decimal point for display purposes without creating new units so that 1 bitcoin is 1 satoshi. This doesn’t increase the supply it just gets rid of the decimals and uses the smallest unit.