Cool, you've flatly refused to assist/present-to the client, and will now be-fired/lose-the-contract.

See why people need to connect to stuff other than what they personally own?

I’ve never had that problem in 25 years of doing this.

Lots of people use lots of ports that aren't USB-C, and are inconvenienced by having to carry dongles and extra cables if their laptop has very few kinds of built-in port. These people have actual needs and reasons behind their behavior. That's all. It's fine that you're not one of them.