This made me laugh. In case it’s a serious question: the excel sheet doesn’t transfer ownership of the tokens to the friend. It would be like writing it down in my notebook.
So how is having a useless token balance recorded on Ethereum any different from having one recorded on a Google Sheet?
And your opinion is my opinion. It's not a good idea because it is not free.
You could create anything worthless that would mean "the token", and that would be enough.
You could use PGP keys if you want it to be private and to run.