Based on my experience with a modded 3ds, many people are willing to spend a few extra minutes on transferring data if they can avoid annoyances with juggling physical media. Unless there’s a common USB mod for the C64, propping your phone up to your C64 for a few minutes might have some appeal from a convenience perspective.
I’m going to disagree with you on the “is Mac better than Windows” front - I think there’s good arguments either way though. At least with a Mac, the end user is still, mostly, who they are designing for. On Windows the end user is becoming the product.