Limiting charge to 2.5w is kind of a dick move, but USB-C standards compliance is such a shit-show that I can't exactly say it's the worst idea I've heard.
I mean, I feel leery enough about plugging into no-name 10w USB chargers; how much am I going to trust in a 100w Guangzhou special? Meanwhile, I'm staring at a Nintendo Switch that I still only have the one USB-C charger for, because there's so much FUD over what chargers will cook it's non-standards-compliant USB-PD implementation.
I mean, I feel leery enough about plugging into no-name 10w USB chargers; how much am I going to trust in a 100w Guangzhou special? Meanwhile, I'm staring at a Nintendo Switch that I still only have the one USB-C charger for, because there's so much FUD over what chargers will cook it's non-standards-compliant USB-PD implementation.