If Bitcoin is KYC, DeFi coins have no hope of replacing the traditional banking system and CBDCs are everywhere, why use Bitcoin at all?
DeFi is not the future, that is where you are mistaking. Bitcoin is something that will exist in future with fiat but not DeFi. The hype around DeFi changed the very nature that DeFi started with. Having seen the days when a much less popular site today, Bitrefill arise from, that is the DeFi that people need. Not stablecoin pools and other passive earning methods.
Governments will likely ban it in the future anyway. China and the US infrastructure bill have already set a precedent for banning mining and development in those countries.
1. Banning bitcoin mining and banning bitcoin are not the same.
2. It is next to impossible to ban bitcoin. For doing so means shutting down complete electricity and internet services - that is not possible for any democratic country do today.
3. Banning mining can happen and a government might choose to take steps to stop people from mining or to regulate mining in a different way that does not interfere with their monetary policy. That is a risk miners have to take.
So no bitcoin is not losing its purpose. If you are using bitcoin you are still serving its purpose. Depending on where you live, you may not be able to spend your bitcoin for paying costs. That does not remove its purpose. Regional differences only show that improvements in usage are needed in future.