That's fine. It's what we have now , and centralized finance has a huge advantage in that there is human review to reverse fraud and theft.
I am perfectly fine using centralised finance to buy things that are mostly already inherently centralized, which is pretty much all common purchases for most people, since buying anything that can be made cheaply by an individual is rare for most.
A huge number of things can be done purely P2P with no payments, with almost no infrastructure. That should be the core feature of Web4.
Even more things can be done semi-decentralized as in BitTorrent+a seedbox, and that works just fine.
Some of those things can even be donation supported in a profitable way and don't need payment from most users in any way that actually connects to the service. They can just put a PayPal and bitcoin link and people can donate however they want.
In Wikipedia can do it, Facebook and maybe even Youtube can, with appropriate P2P load balancing.
This is almost essential because the competing centralized services are totally free(via you-are-the-product models).
An email service or something that costs money and requires linking your bank to some coin payment service is going to have a hard time competing with gmail for the general public.
If something needs payment, it probably shouldn't be a core layer of the whole system. The first priority should be make things too cheap to meter where you can, and then figure out how to decentralize the remaining stuff, assuming there is demand.
Blockchain inherently can't do offline first LAN apps properly, you can't have consensus without communication. If I can't talk to someone on a mesh network without internet, a large amount of the advantage of P2P is gone.