It's ideal to have it as a unit of account, but to achieve a great application of this, it should be automated or understood that it's in "Satoshis". It's challenging if you're using BTC or mBTC, especially for those who are non-tech savvy or relatively new to crypto, but it's a learning curve.
Perhaps, if the technological infrastructure supports it, automation would suffice, and deductions for taxes purchased with it would be easy.
It's not hard to learn about Bitcoin units and in practice, there are some most popularly used units like bitcoins, satoshis, millibitcoins m
BTC.
In addition, with Bitcoin wallet softwares, there are options in wallet settings for choosing which Bitcoin unit you want to display in the wallet. Again, it's not hard to learn for customize your wallet settings.
Units (Bitcoinwiki).[Did you know?] Bitcoin Table of Units.