I’ve had the same thought about the internal modems - do I need this excess hardware that will never be used again? I could possibly save power and reduce weight by 50g or so, but ultimately I have reinstalled just to keep it “complete”.
I can’t remember exactly how, but the modem was able to send and receive faxes. This might save you a few dollars the next time someone needs you to fax them a signed document.
However, here in Australia, analog lines are being phased out and I don’t think the telephone jack on my wall would support a fax call...