> GPC is supported by more laws, like the CCPA, which requires businesses to honor these signals

Because it's off by default? It's the exact same thing, a header with a preset value.

> While DNT broadly addressed tracking, GPC focuses specifically on stopping data from being sold or shared, making it more relevant to today’s privacy needs.

My needs are not being tracked. The tracking is what comes before the selling. I don't want to opt out of selling, I want to opt out of tracking.

> Better adoption potential: GPC was created with input from regulators, privacy advocates, and industry leaders, to align it with existing laws and address previous gaps in functionality.

"Gaps in functionality"? The difference between GPC and DNT is that DNT sends "DNT: 1" and GPC sends "Sec-GPC: 1".

Companies that never respected DNT aren't going to respect GPC. The only difference here is that IE doesn't have GPC enabled by default, but it does have DNT enabled by default.